Nvidia entered the ultra-mobile market in 2008 when it announced the Tegra SoC. Microsoft’s Zune HD media player became the first design win the following year. Between then and now, Tegra processors continued to evolve, and while they appeared in a growing list of devices, they never stood out as premier performers.
In 2013, Nvidia decided to launch its own consumer-oriented products to promote Tegra and Android gaming. One of these was the Tegra Note 7, a 7-inch tablet with some unique features that faced stiff competition from the Nexus 7. The other product Nvidia created was a bit more unique.
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For the Shield, now called Shield Portable, Nvidia wanted to produce something that wasn’t mainstream. A handheld gaming device with an integrated 5-inch 720p screen running Android definitely isn’t going to enjoy the same sales volume as an iPad or Samsung Galaxy phone. However, it found a following within the gaming community, and Nvidia’s presence did lend legitimacy to Android as a gaming platform. While the Shield Portable works well enough for its intended purpose, a specialized design doesn’t allow it to do much else.
Nvidia’s goal for the Shield Tablet is more ambitious: create a device that, first and foremost, is a great tablet, but also happens to be great for playing games. While it’s difficult to design hardware that excels at everything, it would certainly appeal to a wider audience, increasing sales, and, more importantly, emphasizing the advantages of Tegra and attracting game developers to Android.
Shield Tablet Tech Specs
For Nvidia to hit such a high mark, the Shield Tablet requires some powerful and power efficient hardware. Fortunately, the Tegra K1 SoC delivers. Like Tegra 4, the K1 uses four ARM Cortex-A15 cores tuned for high performance and one -A15 companion core that’s optimized for low power. Moving to a 28nm HPM process and a newer-revision architecture allows Nvidia to boost maximum CPU clock rate to 2.2GHz.
Previous Tegra SoCs weren’t held back by CPU performance though. Ironically, it was the GeForce ULP that consistently disappointed. For Tegra K1, Nvidia moves to a much more modern GPU derived from the Kepler architecture. While this mobile-tuned variant is understandably scaled down from the desktop version (Tegra K1 contains a single SMX with 192 CUDA cores), it’s still the same architecture and maintains full software compatibility. For more information about the new GPU and Tegra K1, be sure to read our Nvidia Tegra K1 In-Depth article.
The Tegra K1 is paired with 2GB of DDR3L-1866 RAM and either 16GB of on-board NAND for the Wi-Fi-only model or 32GB for the LTE version. Storage is expandable via microSD (up to 128GB).
Although lacking 802.11ac Wi-Fi support, the Shield Tablet does include 2x2 MIMO 802.11a/b/g/n (2.4 and 5GHz). There’s also Bluetooth 4.0 LE, micro-USB 2.0, and a mini-HDMI 1.4a port for outputting video to an external display.
The LTE version employs Nvidia’s Icera i500 Soft Modem, which includes eight programmable cores running at up to 1.3GHz. These specialized DSP cores are paired with a separate RF transceiver chip and support GSM/GPRS/EDGE, HSPA+ (42Mb/s), and LTE Category 3 (100Mb/s). Since the modem is handled in software, it can be upgraded to support additional standards. Nvidia’s documentation states that the Icera i500 is capable of supporting LTE Category 4 (150Mb/s) with Carrier Aggregation and HSPA+ (84Mb/s), but the Shield Tablet does not support the faster speeds in its initial shipping configuration.
All of this hardware is driven by a 19.75Whr (4938mAh, 4V) non-removable battery. That's roughly 20% less than similar 8-inch tablets like the Xiaomi Mi Pad, Samsung Galaxy Tab Pro 8.4, and iPad Mini with Retina Display. I don’t expect much of a power penalty from the newer revision -A15 cores, since many of ARM’s tweaks were specifically to reduce power draw. The GPU is an unknown, however. It will be interesting to see if Nvidia reduced Kepler’s power envelope to a level acceptable for a tablet. If not, the Shield Tablet’s relatively small battery may be its biggest weakness.
Products
Pricing
SoC
Nvidia Tegra K1
Apple A7
Qualcomm Snapdragon 800 (MSM8974AA)
Nvidia Tegra K1
CPU Core
ARM Cortex-A15 (4+1 Cores) @ 2.2GHz
Apple Cyclone (2 Cores) @ 1.3GHz
Qualcomm Krait 400 @ 2.26GHz
ARM Cortex-A15 (4+1 Cores) @ 2.2GHz
GPU Core
Kepler (192 Core)
PowerVR G6430
Qualcomm Adreno 330 (32 ALU) @ 450MHz
Kepler (192 Core)
Memory
2GB DDR3L-1866
1GB
2GB
2GB LPDDR3
Display
8-inch IPS @ 1920x1200 (283PPI)
7.9-inch IPS @ 2048x1536 (326PPI)
8.4-inch scLCD @ 2560x1600 (359PPI)
7.9-inch IPS @ 2048x1536 (326PPI)
Storage
16GB (Wi-Fi) / 32GB (LTE), microSD (up to 128GB)
16GB / 32GB / 64GB / 128GB
16GB, microSD (up to 64GB)
16GB / 64GB, microSD (up to 128GB)
Battery
19.75Whr (4V, 4938mAh, Non-removable)
23.8Whr (3.75V, 6347mAh, Non-removable)
25.44Whr (5.3V, 4800mAh, Non-removable)
6700mAh (Non-removable)
Camera/s
Front: 5MP HDR / Rear: 5MP HDR, AF
Front: 1.2MP HDR / Rear: 5MP HDR, AF, f/2.4 wide
Front: 2MP / Rear: 8MP AF, LED Flash
Front: 5MP / Rear: 8MP AF, f/2.0 wide
Connectivity
Wi-Fi 802.11a/b/g/n (2x2 MIMO, 2.4 and 5GHz), Bluetooth 4.0 LE, Optional 4G LTE, micro-USB 2.0, mini-HDMI 1.4a
Wi-Fi 802.11a/b/g/n (2x2 MIMO, 2.4 and 5GHz), Bluetooth 4.0, Optional 4G LTE, Lightning Connector
Wi-Fi 802.11a/b/g/n/ac (2.4 and 5GHz), Bluetooth 4.0 LE, micro-USB 2.0
Wi-Fi 802.11a/b/g/n/ (2x2 MIMO, 2.4 and 5GHz), Bluetooth 4.0 LE, micro-USB 2.0
Size
221 x 126 x 9.2mm, 390g
200 x 134.7 x 7.5mm, 331g
219 x 128 x 7.11mm, 331g
202.1 x 135.4 x 8.5mm, 360g
The -A15r3 CPU cores in Tegra K1, now running at comparable clock speeds to Qualcomm’s Snapdragon SoCs, should exceed the performance of all currently shipping CPUs except for Apple’s A7, which still maintains an IPC advantage. The Kepler GPU, with its desktop heritage, should easily outperform the mobile focused architectures of its competitors.
Availability And Options
The Shield Tablet comes in two different configurations: a Wi-Fi only model with 16GB of internal storage for $299 and a Wi-Fi + LTE variant with 32GB of storage for $399. This is the first consumer product that Nvidia is launching worldwide (the Shield Portable and Tegra Note 7 were available in the U.S.-only), and it's currently available from a number of retail outlets in the U.S., Canada and Europe. Additional regions will be added this fall.
The version that comes with a cellular modem supports LTE bands 2, 4, 5, 7, 17 (1900, 1700, 850, 2600, 700) and HSPA+ bands 1, 2, 4, 5 (2100, 1900, 1700, 850) in North America. It comes unlocked and is compatible with AT&T and T-Mobile networks. For those living outside North America, it supports LTE bands 1, 3, 7, 20 (2100, 1800, 2600, 800) and HSPA+ bands 1, 2, 5, 8 (2100, 1900, 850, 900).
Nvidia also offers a cover to protect the Shield Tablet’s screen for $39. It attaches to the side of the tablet with strong magnets and works like Apple’s Smart Cover, turning the screen on or off when it's opened or closed. The flexible cover folds back and also doubles as a stand for holding the tablet upright in landscape mode. There are three sets of magnets inside the back cover; the lower and middle sets allow the cover to prop up the tablet at two different angles. The set near the top holds the cover flat against the back so it doesn’t get in the way when it isn’t needed. The surface of the cover that contacts the screen is a soft felt material, while the exterior has a padded, vinyl-like texture.
The two different angles supported by the Shield Tablet Cover
The other complimentary hardware (or necessity, if you want the full gaming experience) that Nvidia offers is its Shield Controller, available for $59. This wireless controller uses Wi-Fi Direct instead of Bluetooth for communication, which keeps control latency to a minimum. It allows sufficient bandwidth for transmitting bi-directional 16-bit audio (32kHz upstream and 16kHz downstream to the Shield Tablet), which you'll want when a headset and mic are plugged into the controller's headphone jack. Up to four Shield Controllers can be paired with the tablet at one time.
Accessories
The Shield Tablet includes the stylus and also comes with a wall charger and USB cable.
Correction: This article was updated at 1:55 pm ET to clear up confusion regarding the HDMI cable listed among the accessories. Only the press kits come with an HDMI cable — the retail boxes do not include one.
The Shield Tablet has an all-black, stealth fighter-like appearance. With sleek lines and minimal adornment, its inconspicuous exterior hides the game-rendering weaponry inside.
In spite of its plastic chassis, the tablet maintains a premium feel. It’s suitably rigid during normal use, but will flex a bit if you deliberately try to torque or bend it. Adding to the tactile enjoyment is a soft texture on the back cover that feels more like felt than rubber. While it does improve grip, the material isn't particularly sticky. However, I didn’t have any issues with the device slipping through my hands.
Compared to other 8-inch tablets, the Shield tends to be larger and heavier, which is surprising since it has a smaller battery. Even with its more diminutive screen, the Shield Tablet is taller than the Samsung Galaxy Tab Pro 8.4. It’s also 8% thicker and heavier than Xiaomi's Mi Pad, which is already thicker and heavier than the iPad Mini with Retina Display and Galaxy Tab Pro 8.4. While noticeable in a side-by-side comparison, the extra size and weight aren’t really a problem during regular use. I didn’t have any issues using the Shield Tablet with one hand, either.
The Shield Tablet employs an 8-inch IPS screen with a resolution of 1920x1200 (283PPI), which is less than its peers. This display is a compromise between screen quality, price, and battery life. Using a higher-resolution panel would certainly add to the base cost, forcing the Kepler-based GPU to work harder, consequently reducing battery life. Since text on the screen still looks crisp, and the tablet supports HD video, I feel it’s a reasonable concession.
If there’s an optimal screen size and aspect ratio for a “do everything” tablet, I don’t think we’ve found it yet. The Shield Tablet represents Nvidia’s nexus between usability, portability and price. A larger screen would make games more immersive, but reduce portability and increase cost. A larger screen would also be redundant in Console Mode hooked up to a big-screen TV, which is one of the primary use cases for this tablet. Based on these factors, I think Nvidia’s choice is reasonable, although I personally prefer larger tablets. At least the Shield Tablet eschews the 16:9 form factor. Its 16:10 aspect ratio works better for general tablet use, particularly in portrait mode.
Surrounding the screen is a comparatively thick bezel, especially along the top and bottom. While this adds to the tablet’s overall height, it does give your thumbs a place to rest as you hold on in landscape mode. The screen is flanked by pair of front-facing stereo speakers (a nice touch for a gaming-centric tablet). The only other feature on the front is a 5MP fixed-focus camera with HDR that’s centered in the upper speaker grille.
The back has a simple matte black appearance, rather than the Tegra Note 7's more aggressive-looking stippled back. The only highlights are a slightly recessed, gloss-black Shield branding and the 5MP rear camera with HDR and auto-focus surrounded by a small chrome ring.
The micro-USB 2.0, mini-HDMI 1.4a and headphone jack reside on the top edge, along with one of the bass reflex ports. There’s another port on the bottom edge.
On the left edge are two slots that engage the Shield Tablet Cover and help hold it in place. The power button is located on the top-right edge in portrait mode, which becomes the top edge in landscape. Below the power button is the one-piece volume rocker, and below that is a covered microSD slot. Further down is another door that appears to be for the micro-SIM card (our review unit is a Wi-Fi only model). The stylus is securely stored in a port in the bottom-right corner.
The Shield Controller is naturally modeled after the Shield Portable, with a similar control layout and feel. Its shape is comfortable, but a bit undersized for my large hands. The balance feels just right; it’s not overly heavy. Gaming controls consist of a D-pad, dual clickable analog sticks, four buttons (X, Y, A, B), two bumpers, and two triggers.
My only complaint about the controls is that the trigger buttons' throw is a bit long. It doesn’t take much travel to activate them, while there’s a lot of extra travel afterwards that doesn’t seem necessary. To be fair, my trigger finger is accustomed to a mouse button, so gamers more accustomed to a controller might not share my opinion.
The controller offers additional features beyond the obvious. Its green, triangular Nvidia button turns the controller on/off, pairs it with the tablet and launches the Shield Hub app. Surrounding the Nvidia button are three capacitive buttons used for navigating within games and the Android UI. Centered below the triangle is the Home button, which functions as the standard Android Home button. Double-tapping it opens the task switcher and long-pressing launches Google Now for issuing voice commands (a microphone is located above the triangular Nvidia button). There’s also a Back button for Android that, when long-pressed, opens the Nvidia Share menu for connecting to Twitch, offline recording and taking screenshots. The Start button may be used for PC gaming functions.
The right joystick controls an on-screen mouse cursor. For finer control, or when the right joystick is unavailable during a game, there’s a small capacitive, clickable touch pad for mouse navigation duties. Its sensitivity is adjustable, and while not as smooth as a laptop track pad, it works well enough for basic navigation. If the tablet is out of reach (like when it’s connected to a TV) and you find it necessary to enter some text, the touch pad works with the on-screen keyboard. That's not ideal, obviously, but it's far better than using a numeric keypad on a TV remote.
Below the touch pad is a momentary rocker switch for controlling volume. Pressing both sides simultaneously mutes the sound, which is the only functionality it provides when connected to a TV.
The front of the controller has a micro-USB 2.0 port for charging the Li-ion battery and a headphone jack that supports headsets with microphones. Having the headphone jack on the controller is convenient; it maintains the absence of wires between you and the tablet.
The Shield Tablet ships with Android 4.4.2 KitKat and is devoid of custom skins, launchers, widgets and other gee-whiz features that do nothing except get in the way. Nvidia’s only additions to the stock Android experience are some Shield-specific settings for the controller and stylus, along with several apps to enable gaming and stylus functionality. Kudos to Nvidia for providing a clean, uncluttered interface.
The home screen includes two folders in the lower-left corner that conveniently hold all of the Google and Nvidia apps, respectively, making it easy to access Google features and Shield-specific content. There are also dedicated buttons for the Shield Hub app and app drawer in the dock.
Nvidia could have created a custom skin to make the Shield Tablet’s gaming- and media-oriented features pervasive throughout the UI. Instead, the company bundles all of that functionality into the Shield Hub app, a design decision that doesn’t intrude upon the general-purpose tablet experience.
The Shield Hub app is simple to navigate and designed to be easily viewed on a TV from across the room. From within the app, you can shop for Shield-optimized games and accessories, and read gaming news. It also provides easy access to more general Android-based titles and media apps like Netflix. Any Shield tested and certified games/apps show up in the appropriate category automatically. Unfortunately, there’s currently no way to manually add Android games or apps, which keeps the Shield Hub from being an exclusive interface while in console mode.
This isn’t the case for accessing PC games via GameStream. Titles added by selecting Preferences, then Gamestream in the GeForce Experience App on the PC appear in the “My PC Games” section of the Shield Hub app.
Checking out gaming news from within Shield Hub
The Shield Wireless Controller app is simple and self-explanatory. Its sole purpose is to make pairing Shield Controllers with the tablet a painless procedure.
The interface for the Shield Wireless Controller app
In addition to the Shield-specific apps, the tablet comes preloaded with Adobe Reader and Camera Awesome. For capturing notes and general writing, you get Evernote, JusWrite and Write.
By focusing on simplicity and functionality, Nvidia provides a pleasant and efficient interface for Shield. Other than the inability to customize which apps appear within the Shield Hub, the only other quibble I have relates to color consistency. Nvidia uses a bright green accent shade for both hardware and software. However, Android uses blue for its highlight color. Using Nvidia green throughout the Android UI, as well as its own apps, would yield a more integrated experience.
The Shield Tablet, foregoing the extra cost of an active digitizer, uses Nvidia’s DirectStylus 2, an upgraded version of the inking technology found in the Tegra Note 7, to improve upon the normal passive capacitive stylus experience. DirectStylus 2 employs the Kepler GPU to analyze up to 300 scans per second from the touch sensor, enabling features like pressure sensitivity and palm rejection.
Unlike other passive styli, the included chisel-tip utensil doesn’t obscure the point of contact with the screen, which makes it feel more like using a pen rather than a large, blunt crayon. The sharp tip also creates much finer lines, and there’s generally no discernible lag between it and the trail of ink.
Along with DirectStylus 2, the Shield Tablet has built-in multi-language handwriting recognition. Instead of sending your scribbles off to a remote server for OCR processing, however, the Shield Tablet taps into the power of its Kepler GPU for on-board processing. This solution not only maintains privacy, but also improves performance by removing network latency and continues to function, even offline.
In order to use handwriting recognition, it needs to be manually enabled from within the settings menu. Choosing between keyboard or handwriting mode falls under Settings—>Language & Input. Next, select “Default” under the “Keyboard & Input Methods” section and choose “Handwriting Recognition” or one of the installed on-screen keyboards. Frequently switching between the different modes gets annoying after a while. It would be nice if there was an always-present button on the keyboard to quickly toggle between modes without messing around in the settings.
With handwriting recognition enabled, an input field that accepts written text replaces the on-screen keyboard. Writing is processed in real-time, but the engine waits until you pause before replacing handwritten letters with their digital equivalents. There’s a bar along the top with shortcuts for automatically completing recognized words and it supports several pen gestures for manipulating the text, like scribbling out a character to delete it, drawing a vertical line between characters to split them and drawing a “u” below characters to remove the space between them.
Character recognition is nearly instantaneous and accuracy is very good, even with cursive writing. The one complaint I have is that the Android navigation buttons are always present when the handwriting input field is active, even in Fullscreen Mode. Being right-handed, resting my hand on the screen engages either Lasso Mode or opens the task switcher, thus forcing my hand to hover uncomfortably above the screen while writing.
The DirectStylus Launcher, a menu that opens automatically by removing the stylus, provides quick access to stylus-ready apps. If you prefer, you can modify this behavior to open a specific app or do nothing at all instead. The menu is also accessible by manually selecting the DirectStylus Launcher app in the app drawer or by adding it to the home screen.
Adding and removing apps from the menu is accomplished by tapping the “Add” button; there’s even a shortcut to the DirectStylus options in the Settings menu. It’s a simple app that helps integrate the stylus with the tablet.
Removing the stylus from its holster also adds two buttons to the Android navigation bar (just one of several reasons to ditch fixed hardware buttons). The button on the left locks out all touch inputs except for the stylus. This includes the Android navigation bar itself. While the palm rejection algorithm is always active (excluding the Android navigation bar) and works well, it’s not 100% effective. The stylus-only mode takes palm rejection to a higher level and eliminates all spurious inputs from biological sources. Engaging it also eliminates the palm interference issue discussed above when using the handwriting input field, although this adds an extra step.
The other additional button is for lasso capture mode, which provides a simple pen tool for annotating the screen, along with several screen capture options, including whole screen, rectangular region and free-hand (lasso) region. Once a screenshot is taken, there are options for saving it to the photo library as a .png file or sharing it with several external services like Dropbox, Google Drive, Evernote and email.
While the stylus enhances note-taking and sketching, Nvidia gives digital artists something as well. Dabbler is the company's new painting app built specifically to take advantage of the features and performance of DirectStylus 2 and Nvidia's GPU. There are three distinct painting modes, each with its own unique GPU-accelerated effects: standard pen with shape recognition, watercolor and oil. Since this app relies heavily upon the DirectStylus technology, input is limited to the stylus only.
The standard pen mode includes an option for smart shape recognition. Draw something that looks like a triangle and Dabbler will “fix” it, straightening and connecting the edges. In watercolor mode, the paint absorbs into the paper as it dries and, with gravity activated, the wet paint flows based on the gyroscope's orientation. Oil painting effectively uses 3D lighting and texture effects, allowing paint to be built-up in layers and then trimmed away with the chisel tool. Changing the orientation of the light source drastically alters the appearance of the painting as the highlights and shadows change in real-time.
While my artistic skill stops at stick figures, I found the app easy and fun to use. The 3D graphics and physics are more than just visual eye candy; GPU assistance adds a greater sense of realism.
Overall, the OS interface is clean and Nvidia’s software adds to the tablet experience without being intrusive, leaving little to complain about. The stylus integration and Dabbler painting app are also nicely done, but the Shield Tablet’s gaming features are the big draw.
Nvidia’s core strength is gaming and the Shield Tablet packs the necessary hardware to repel an alien invasion or horde of zombies, and enough games to keep the battle raging for hours.
The front-facing speakers get loud and remain distortion-free. However, the small drivers lack any real bass punch. At default settings, the sound is flat and tinny, particularly vocals on music tracks. But a few tweaks with the equalizer help the low- and mid-range frequencies sound a bit warmer. The stereo speakers do a nice job with positional audio cues while gaming.
Console Mode
Hooking the Shield Tablet up to an HDTV via mini-HDMI allows it to function like a game console, bringing Android and PC games to the big screen with support for up to four wireless Shield Controllers.
In Console Mode, the Shield Tablet becomes a conduit between content and the TV, not just for games, but for videos and music as well. The source could be the local microSD card; streaming services like Netflix (including full 1080p support), Hulu, YouTube, or Pandora; or your own media server with the help of a third-party app.
Shield Tablet Console Mode interface
There are two different options for displaying content on the TV. In Mirror mode, the tablet display remains active and is mirrored on the TV. Since there’s a resolution mismatch between the tablet’s display (1920x1200) and the TV (1920x1080), some content will be letterboxed. This isn’t always true for video streams, however, because they are sent to the TV at the encoded resolution.
The second option is Console mode, which turns off the tablet’s display and does away with letterboxing by changing the native resolution on the tablet to 1920x1080 to match the TV. Switching to this mode closes all open applications and reboots the tablet.
GameStream
GameStream is the key to playing your PC games in bed, the backyard, or even down the street at the coffee shop. A proprietary technology, GameStream utilizes a GeForce GTX 650 or better graphics card (Kepler-based GTX 600M or higher mobile GPU) to render the game on the PC with the NVEnc hardware-based encoder. The resulting H.264 video stream is then sent over Wi-Fi or the Internet to a Shield Portable or Shield Tablet, which uses its Nvidia GPU’s PureVideo HD feature for decoding the stream. GameStream supports 720p video over wireless connections and 1080p over Ethernet using an optional Ethernet-to-USB adapter at up to 60 frames per second.
In addition to the GPU requirements, GameStream requires the GeForce Experience application and Nvidia's latest drivers on a PC running Windows 7 or newer. For streaming over Wi-Fi, Nvidia recommends at least an 802.11a/g router, but preferably an 802.11n dual-band router. Streaming PC games over the Internet calls for a minimum symmetric bandwidth of 5Mb/s. In the article Shield Remote GameStream: How Far Will You Go to Game?, we examine how well GameStream works over several different connections using the Shield Portable.
Playing PC games on a tablet from nearly anywhere you want is certainly cool, but not flawless. I found the games I purchased through Steam to work best, while some of my older titles on DVD had issues. First, most games on optical disc require it physically present to play. Launching a game on the Shield and then running downstairs to pop a disc into your drive breaks the mood. The second issue involves game controller support, or rather a lack thereof. Even though Nvidia lists support for BioShock 2, my version on DVD wouldn’t recognize the Shield Controller, nor was there any way to enable support from within the options menu.
BioShock Infinite and Fallout 3, both purchased through Steam, worked well and even referenced the controller inputs rather than keyboard/mouse commands in the on-screen instructions. Portal 2 also worked after manually enabling controller support from within the game.
After seeing how well GameStream worked with some of my Steam games, I decided to push the compatibility boundary by breaking out some really old games. Since Star Wars: The Force Unleashed is a console port, I thought it might work. However, it didn’t recognize the controller and rendered at the wrong resolution in a tiny window. It’s not a very good game anyway, so no big loss. Next, I tried The Chronicles of Riddick: Escape from Butcher Bay, one of the better film adaptations in my opinion. But it didn’t recognize the controller inputs either. The lesson here is to ditch the DVDs and stick with Nvidia’s list of compatible GameStream games for best results.
Not wanting to concede defeat, I paired a Bluetooth keyboard and mouse with the Shield Tablet and fired up GameStream again (I’m way better with a mouse than a thumbstick anyway) and was pleasantly surprised. Not only did the officially supported games work with no discernible input lag, but the older, unsupported games like Chronicles of Riddick and my DVD version of BioShock 2 worked as well.
Other than some compatibility issues with older games, GameStream works and is a great way to extend PC gaming beyond a desk and even to an HDTV when used in conjunction with Console Mode. Using an Asus RT-AC66U 802.11ac dual-band router and a GeForce GTX 760 in my PC, frame rates remained fluid and there wasn’t any input lag. One quirk I noticed is that exiting the game to the Android home screen or back to the Shield Hub app doesn’t automatically pause the game. The game is still running live on the PC with your character standing in place like an idiot while getting shot. To keep this from happening, it’s necessary to pause the game first by using the correct button on the Shield Controller before exiting.
Nvidia isn’t the only company to recognize the benefit of remote rendering and streaming PC games. Valve offers a similar service with Steam In-Home Streaming. It works in a very similar way to GameStream, rendering games on a PC and streaming an H.264 video stream to a client on the same network. Unlike GameStream, the Steam solution is GPU agnostic and works with Windows, OS X and Linux. However, it doesn’t work with tablets, instead requiring another PC or laptop as the client.
Nvidia Grid
GameStream plus the cloud equals Nvidia Grid. Rather than using a local PC for rendering, Nvidia’s servers handle the pixel wizardry and stream H.264 video over the Internet to a Shield portable device running the Nvidia Grid app, available for free from the Play Store. The service also requires an Internet connection with at least a 10Mb/s download speed and 40ms ping times to the Grid servers.
Nvidia Grid is currently in beta with game servers singly located in San Jose, CA, which may degrade the experience for those outside the western U.S. For gamers who aren’t geographically challenged, the service is free during the beta phase. As of now, there are 18 titles available. Check out the Nvidia Grid Cloud Gaming Beta page for more information.
I played some of the games at different times spread over a couple of weeks. Living in close proximity to California and with a connection rated for 50Mb/s down and 10Mb/s up, I found the Grid gaming experience to be generally excellent. The video was smooth and there wasn’t any conceivable input lag, myself being about average in lag sensitivity. Only a single gaming session was marred by lagging inputs.
I see a bright future for Nvidia Grid and other similar cloud gaming services, freeing us from the tedium of downloading, installing and updating games; no more license keys or intrusive DRM. Nvidia will need more game servers to expand Grid’s reach and more games to broaden its appeal, but the potential is obvious.
ShadowPlay And Twitch
The Shield Tablet includes Nvidia’s ShadowPlay screen recording technology. Like the desktop version, ShadowPlay on the tablet directly accesses the frame buffer at a low level and then passes the frames to the NVEnc hardware H.264 video encoder. In addition to capturing a video of the screen, regardless of what app or game is in use, buttons along the top of the Nvidia Share menu individually toggle options to record audio from the microphone, overlay video from the front facing camera or even overlay a chat window. The size, location and opacity of the chat and front camera video overlays are adjustable.
There are two different options for video recording. Manual Record allows precise control of when to start and stop recording. The Auto Record mode, once it starts, continuously records video into a fixed length rolling buffer like a DVR, which works well for capturing your prowess while gaming. It also keeps videos from consuming too much valuable storage space. The buffer is user configurable for durations of 1, 3, 5, 10 or 20 minutes. There are also four different quality settings for capturing video: low (360p, 25FPS), medium (480p, 30FPS), high (720p, 30FPS), and ultra (1080p, 30FPS). All four modes use a variable bit rate.
ShadowPlay also enables the Shield Tablet to broadcast live gaming sessions, complete with your eloquent commentary from the integrated microphone and video overlay of your noble face from the front camera, directly to Twitch.
If the Shield Tablet is to be considered a great gaming device, it needs access to a large library of quality titles. Fortunately, the Android ecosystem has a vast array of touch-enabled games, immediately accessible on the Google Play Store. Adding the Shield Wireless Controller, or any Bluetooth controller, opens up even more possibilities. Nvidia claims there are more than 400 Tegra-optimized touch- and controller-based games for Android, like GT Racing 2, War Thunder and several Grand Theft Auto titles, along with a growing list of games that have been specifically enhanced for Tegra K1. Nvidia provides a list of compatible games on the Shield website.
Both Half Life 2 and Portal look better running on Tegra K1 thanks to several bonus features, including bump mapping, environment mapping, flashlight shadow maps, specular highlights, motion blur and higher-quality texture filtering. Rochard supports 1080p rendering versus 720p for Tegra 4. The lighting model used for Pure Chess is equivalent to the PS4 version of the game and also supports depth-of-field and bloom effects. Anomaly 2 includes PhysX support, and Talos Principle adds full dynamic shadows for all objects, parallax texture mapping, specularity and reflections and geometry environments with greater detail.
Nvidia also provides a feature called Gamepad Mapper, which adds game controller support to native Android touchscreen games. Players can create custom gamepad mapping profiles and share them with their friends.
PC gamers gain access to more than 120 officially supported GameStream-ready PC titles. Assassin’s Creed IV: Black Flag, Batman: Arkham Origins, Battlefield 4, Call of Duty: Ghosts, Far Cry 3 and Titanfall are just a few, with a full list available from Nvidia. Additional games may also work if a Bluetooth keyboard and mouse are used instead of a game controller.
Nvidia Grid is currently limited to 18 games, including Borderlands, Borderlands 2, Race Driver Grid, Saints Row: The Third, The Witcher 2: Assassins of Kings and Trine 2.
It will be interesting to see what impact Tegra K1 and its Kepler architecture have on mobile gaming. Supporting both OpenGL 4.4 and DirectX 12, in addition to OpenGL ES 3.1, should make it much easier for developers to port PC and game console titles to Android devices with Tegra K1. One example is Trine 2: Complete Story, which requires Tegra K1 and comes bundled with the Shield Tablet. With full OpenGL support, it allowed Frozenbyte to quickly port the PC version of the game using the same OpenGL render path, complete with PhysX support.
Will we see an influx of mobile games from the Xbox 360 and PS3 catalogs, or even new titles, with some of the detail dialed back, launching alongside the PC and console versions? I asked Manish Sirdeshmukh, Product Manager for Adreno Graphics and Gaming, if Qualcomm had any plans to support the full OpenGL specification like Tegra K1 in future Adreno GPUs. He stated that OpenGL 4.4 doesn’t add anything significant beyond what is already supported in OpenGL ES, and that he hasn’t seen any demand from game developers to support the full OpenGL specification. It seems the significance of Kepler’s arrival in mobile will ultimately be determined by its market penetration.
Benchmark Suite
Our current Android test line-up comprises six key sections: CPU, Web, GPU, GPGPU, Display and Battery.
HTML5 And JavaScript Benchmarks | JSBench, Peacekeeper 2.0, WebXPRT 2013 |
|---|---|
CPU Core Benchmarks | AnTuTu X (Anti-Detection), Basemark OS II Full (Anti-Detection), Geekbench 3 Pro (Anti-Detection), MobileXPRT 2013 |
GPU Core Benchmarks | 3DMark (Anti-Detection), Basemark X 1.1 Full (Anti-Detection), GFXBench 3.0 Corporate |
GPGPU Benchmarks | CompuBenchRS |
Display Measurements | Brightness(Min/Max), Black Level, Contrast Ratio, Gamma, Color Temperature, Color Gamut (sRGB/AdobeRGB) |
Battery Tests | Basemark OS II Full (Anti-Detection), BatteryXPRT 2014, GFXBench 3.0 Corporate |
Test Methodology
All handsets are benchmarked on a fully updated copy of the device's stock software. The table below lists other common device settings that we standardize to before testing.
Bluetooth | Off |
|---|---|
Brightness | 200 nits |
Cellular | SIM card removed |
Display Mode | Device Default (nonadaptive) |
Location Services | Off |
Power | Battery |
Sleep | Never (or longest available interval) |
Volume | Muted |
Wi-Fi | On |
Furthermore, for browser-based testing on Android, we employ a static version of the Chromium-based Opera in order to keep the browser version even across all devices. Due to platform restrictions, Safari is the best choice for iOS-based devices, while Internet Explorer is the only game in town on Windows RT.
Comparison System Specs
We’ll be pitting the Shield Tablet and its Tegra K1 SoC against an assortment of tablets, big and small, and new and old. As the Shield Tablet’s predecessor, the EVGA Tegra Note 7 with Tegra 4 SoC will demonstrate Nvidia’s progress. Since we don’t have benchmark results for the iPad Mini with Retina Display, a closer competitor to the 8-inch Shield Tablet, we’ll use the iPad Air running Apple’s A7 SoC instead. The Galaxy Note 10.1 (2014) Wi-Fi represents Samsung’s Exynos 5 Octa 5420, while the Galaxy Note 10.1 (2014) LTE uses the popular Qualcomm Snapdragon 800. Finally, Qualcomm’s Snapdragon 805 MDP reference tablet will showcase the performance of Qualcomm’s highest-performing SoC.
The table below contains all the pertinent technical specifications for today’s comparison units:
Products
Pricing
Operating System
Google Android 4.4.2
Google Android 4.2.2
Google Android 4.4.2 w/Samsung TouchWiz UI
Google Android 4.4.2 w/Samsung TouchWiz UI
Google Android 4.4
Apple iOS 7.1
SoC
Nvidia Tegra K1
Nvidia Tegra 4 (T114)
Samsung Exynos 5 Octa (5420)
Qualcomm Snapdragon 800 (MSM8974AA)
Qualcomm Snapdragon 805
Apple A7
CPU Core
ARM Cortex-A15 (4+1 Core) @ 2.2 GHz
ARM Cortex-A15 (4 Core) @ 1.8 GHz
ARM Cortex-A15 (4 Core) @ 1.9 GHz + ARM Cortex-A7 (4 Core) @ 1.3 GHz
Qualcomm Krait 400 (4 Core) @ 2.26 GHz
Qualcomm Krait 450 (4 Core) @ 2.7 GHz
Apple Cyclone (2 Core) @ 1.3 GHz
GPU Core
Kepler (192 Core)
Nvidia GeForce ULP (72 Core) @ 672 MHz
ARM Mali T628MP6 (6 Core) @ 600 MHz
Qualcomm Adreno 330 (32 ALU) @ 450 MHz
Qualcomm Adreno 420
Imagination PowerVR G6430 (4 Cluster) @ 200 MHz
Memory
2 GB
1 GB LPDDR3
3 GB LPDDR3
3 GB LPDDR3
3 GB LPDDR3
1 GB LPDDR3
Display
8-inch IPS @ 1920x1200 (283 PPI)
7-inch IPS @ 1280x720 (441 PPI)
10.1-inch TFT @ 2560x1600 (299 PPI)
10.1-inch TFT @ 2560x1600 (299 PPI)
10.06-inch IPS @ 2560x1440
9.7-inch IPS @ 2048x1536 (264 PPI)
Battery
19.75 Watt/Hour (Non-removable)
4100 mAh (Non-removable)
8220 mAh (Non-removable)
8220 mAh (Non-removable)
3400 mAh (Removable)
8820 mAh (Non-removable)
The two Nvidia powered devices should bracket the GPU performance results, but how close will Adreno 420 be to Tegra K1? Apple’s A7 should still dominate the single-core CPU benchmarks, but the higher clocked -A15 cores in Tegra K1 are expected to close the performance gap.
AnTuTu X
AnTuTu is an Android system benchmark designed to test the performance capabilities of four major aspects of mobile devices: Graphics (encompassing 2D, UI and basic 3D), CPU (fixed, floating-point and threading), RAM (read and write), and I/O (read and write).
The Shield Tablet easily outscores the other devices in this system benchmark thanks to its Kepler GPU, which is more than twice as fast as Qualcomm's latest Adreno 420 GPU in the Snapdragon 805 SoC! Kepler’s advantage is specific to the 3D graphics sub-test though, with the Adreno 420 equaling its 2D score.
All three -A15-based SoCs outscore Snapdragon’s Krait architecture in the CPU test. The higher-clocked, newer revision -A15 cores in Tegra K1 show a 23% advantage over Samsung’s Exynos 5 Octa.
Snapdragon 805’s 25.6GB/s of memory bandwidth give it the highest score in the RAM test, while the Shield Tablet places second with its 14.9GB/s.
Basemark OS II Full (Anti-Detection)
Basemark OS II is an all-in-one tool designed for measuring overall performance of mobile devices. It scores each device in four main categories: System, Memory, Graphics and Web. The System score reflects CPU and memory performance, specifically testing integer and floating-point math, along with single- and multi-core CPU image processing using a 2048x2048-pixel, 32-bit image. Measuring the transfer rate of the internal NAND storage (Memory) is done by reading and writing files with a fixed size, files varying from 65KB to 16MB, and files in a fragmented memory scenario. Calculating the Graphics score involves mixing 2D/3D graphics inside the same scene, applying several pixel shader effects, and displaying 100 particles with a single draw call to test GPU vertex operations. The benchmark is rendered at 1920x1080 off-screen 100 times before being displayed on-screen. Finally, the Web score stresses the CPU by performing 3D transformations and object resizing with CSS, and also includes an HTML5 Canvas particle physics test.
Another impressive performance for Tegra K1 with a 2.5x advantage over Snapdragon 805 in the Graphics test. It’s also six times faster than the PowerVR G6430 GPU in the iPad Air and 22x faster than the feeble GeForce ULP GPU in the Tegra 4.
Apple’s A7 remains unbeaten in the CPU-centric System and Web tests.
Geekbench 3 Pro (Anti-Detection)
Primate Labs' Geekbench offers a wide selection of cross-platform compatibility, with apps available for Windows, OS X, Linux, iOS and Android. This simple system benchmark produces two sets of scores: single- and multi-threaded. For each, it runs a series of tests in three categories: Integer, Floating Point and Memory. The individual results are used to calculate category scores, which, in turn, generate overall Geekbench scores.
The A7 in the iPad Air posts the highest scores, even though it operates at the lowest frequency. Its emphasis on execution width and larger caches proves to be the winning formula.
Snapdragon 805 falls behind Tegra K1 once again in CPU performance, with about a 13% deficit. Compared to the lower-clocked -A15 cores in the Exynos 5 Octa, the Tegra K1’s performance scales almost perfectly with clock speed.
With half as many CPU cores as its competitors, the A7 drops out of first place in the Multi-Core test, yielding the position to the Tegra K1.
Snapdragon 805 shows off its superior memory bandwidth. However, its Integer and Floating Point scores are lower than the Snapdragon 800 in the Galaxy Note 10.1 LTE, which itself is about 23% slower than the Shield Tablet in the same tests.
MobileXPRT 2013
Principled Technologies' MobileXPRT 2013 is a modern SoC benchmark for Android. It consists of 10 real-world test scenarios split into two categories: Performance and User Experience.
The Performance suite contains five tests: Apply Photo Effects, Create Photo Collages, Create Slideshow, Encrypt Personal Content and Detect Faces to Organize Photos. Performance results are measured in seconds. The User Experience suite also has five tests: List Scroll, Grid Scroll, Gallery Scroll, Browser Scroll and Zoom and Pinch. These results are measured in frames per second. The category scores are generated by taking a geometric mean of the ratio between a calibrated machine (Motorola's Droid Razr M) and the test device for each subtest.
Despite its 16% clock rate advantage, the Tegra K1 posts essentially the same scores as the Exynos 5 Octa in every test. These benchmark results don’t align with either CPU frequency or memory bandwidth and are difficult to explain.
The unit of measure for the User Experience Tests is frames per second. Values for each individual test are shown within the bar graph. The number to the right of each bar is the computed score; higher is better.
The Shield Tablet is pretty much limited by v-sync in every test except Gallery Scroll. All of the devices are within 10% of each other and provide acceptable frame rates.
The tests on this page are JavaScript- and HTML5-heavy selections from our Web Browser Grand Prix series. Such tests are extremely meaningful to mobile devices because so much of the in-app content is served via the platform's native Web browser. These tests not only offer a view of each device's Web browsing performance, but since these tasks are traditionally so CPU-dependent, browser benchmarks (especially JavaScript-heavy tests) are a great way to measure SoC performance among devices using the same platform and browser.
JSBench
Unlike most JavaScript performance benchmarks, JSBench could almost be considered real-world, since it utilizes actual snippets of JavaScript from Amazon, Google, Facebook, Twitter and Yahoo.
JSBench doesn’t take advantage of more than two cores and seems insensitive to CPU clock rate, its performance primarily dependent on CPU architecture. Apple’s A7 posts the best time followed by the three SoCs with -A15 cores. Krait doesn’t handle this benchmark well, posting the two worst times.
The one anomaly is Tegra K1, completing the benchmark 20% faster than both the Tegra 4 and Exynos 5 Octa. It’s tempting to ascribe this result to K1’s frequency advantage, which is about the same percent difference. However, none of the other SoCs sharing the same CPU architecture see any benefit from frequency scaling or additional memory bandwidth. All three SoCs also use the same 2MB L2 cache. Tegra K1 does use the newer revision -A15 cores (r3p3), but looking through the ARM revision history only reveals “engineering errata fixes” and some additional clock gating features introduced in r3p0. There's nothing that would explain a 20% performance improvement.
Peacekeeper 2.0
Peacekeeper is a synthetic JavaScript performance benchmark from Futuremark.
We see nearly the exact same trend in Peacekeeper. The iPad Air holds a 24% advantage over the Shield Tablet, which is 23% faster than the other two SoCs with -A15 cores.
WebXPRT 2013
Principled Technologies' WebXPRT 2013 is an HTML5-based benchmark that simulates common productivity tasks traditionally handled by locally-installed applications, including photo editing, financial charting and offline note-taking.
Tegra K1 isn’t able to break the A7s dominance in our browser benchmarks, only achieving 81% of its high score. The Exynos 5 Octa matches Tegra K1s performance, but Tegra 4 trails behind. Curiously, Qualcomm’s highest-clocked Snapdragon, the 805, comes in last, trailing the lower-clocked Snapdragon 800 in the Samsung Galaxy Note 10.1 LTE.
3DMark (Anti-Detection)
Futuremark has become a name synonymous with benchmarking, and the company's latest iteration of 3DMark offers three main graphical benchmarks: Ice Storm, Cloud Gate and Fire Strike. Currently, the DirectX 9-level Ice Storm tests are cross-platform for Windows, Windows RT, Android and iOS.
Ice Storm simulates the demands of OpenGL ES 2.0 games using shaders, particles and physics via the company's in-house engine. Although it was just released in May of 2013, the on-screen portions of Ice Storm have already been outpaced by modern mobile chipsets, with Nvidia's Tegra 4 and Qualcomm's Snapdragon 800 both easily maxing-out the Extreme version (1080p with high-quality textures). However, Ice Storm Unlimited, which renders the scene off-screen at 720p, is still a good gauge of GPU-to-GPU performance.
GPU performance expectations are high for Nvidia’s Tegra K1 and it doesn’t disappoint, posting the highest Physics and Graphics scores. Its final score is 1.56x better than the Adreno 420 in Snapdragon 805. Looking only at the Graphics test, the Tegra K1 puts its 192 CUDA cores to good use, outscoring the Adreno 420 and PowerVR G6430 by a factor of about 1.77x. If this result is typical, Qualcomm and Imagination will need to work hard to match Kepler’s performance.
Basemark X 1.1
Based on the Unity 4.0 game engine, Rightware’s Basemark X is a cross-platform graphics benchmark for Android, iOS, and Windows Phone 8. This test utilizes Unity’s modern features via the OpenGL ES 2.0 render path to simulate how a game might look and run. Basemark X is an aggressive test that still hasn’t been maxed out by the latest mobile SoCs.
Tegra K1’s margin of victory over the Adreno 420 at Medium Quality is only 14%, but it's almost twice as fast as the Tegra 4 in Nvidia’s previous tablet offering. Not a bad performance gain in just one generation!
The finishing order is unchanged at the higher quality setting, but Tegra K1’s lead increases to 51% over the Adreno 420. It also leaves the iPad Air looking a bit deflated, besting it by a factor of two.
GFXBench 3.0 Corporate
Kishonti GFXBench 3.0 is a cross-platform GPU benchmark supporting both the OpenGL ES 2.0 and OpenGL ES 3.0 APIs. It comprises both “high-level” game-like scenarios, along with more “low-level” tests designed to measure specific subsystems.
Among the high-level tests are Manhattan and T-Rex. Manhattan is a modern, complex OpenGL ES 3.0-based test, while the OpenGL ES 2.0-level T-Rex is a holdover from GFXBench v2.7.
The low-level tests include Fill, which measures fill rate by rendering four layers of compressed textures; Alpha Blending, a test that renders layers of semi-transparent quads using high-resolution, uncompressed textures; ALU, for measuring shader compute performance and Driver Overhead, which measures the CPU overhead of the graphics driver and API by making a lot of draw calls and state changes.
See GFXBench 3.0: A Fresh Look At Mobile Benchmarking for a complete test-by-test breakdown of this benchmark.
The Shield Tablet looks particularly impressive running T-Rex. In Offscreen rendering, it’s 1.8x faster than the Snapdragon 805 reference tablet and a staggering 2.7x faster than the iPad Air. It also has no problem running T-Rex smoothly at the screen’s native resolution.
The Shield Tablet maintains nearly the same advantage over its closest two competitors in the more demanding Manhattan benchmark and almost breaks the 30FPS barrier rendering at its native screen resolution.
The Alpha Blending test shows the two Adreno GPUs out front and an uncharacteristic drop-off in performance for Tegra K1. It’s Achilles heel may be memory bandwidth since it doesn’t seem to handle the high-resolution, uncompressed textures used in this test very well.
Tegra K1’s 1.8x advantage reappears in the compute-intensive ALU test. Shader performance is definitely Kepler’s strength.
Snapdragon 805 wins the Fill test with its superior memory bandwidth. Tegra K1 falls to second place, but still offers twice the Fill performance as Apple’s A7.
Graphics performance is the biggest test for a gaming device, and the Shield Tablet passes with flying colors. Nvidia’s Tegra K1 is at the head of the mobile GPU class, busting the curve that all other SoCs are graded on.
Correction: This article was updated at 10:00 pm ET to include results based on a new firmware v1.2.1 from Nvidia (released OTA on 10/9/14) that fixed the driver bug causing erroneous results for CompuBenchRS. This page should replace the original page in the posted article.
CompuBenchRS
CompuBenchRS tests the compute performance of multi-core systems supporting the RenderScript API (a component of the Android operating system). The compute API is similar to CUDA or OpenCL, and can distribute parallel tasks across all compute cores, including the CPU and GPU (as of Android 4.2, RenderScript is expanded to run on the GPU, in addition to the CPU of supported systems). On compute-capable GPUs, the benchmark runs on the graphics engine. Otherwise, the tests stress CPU cores. CompuBenchRS sub-tests cover the following categories: Computer Vision (Face Detection), 3D Graphics (Provence - ray tracing), Image Processing (Gaussian Blur, Histogram), Physics (Particle Simulation – 4K), and Throughput (Julia Set, Ambient Occlusion).
The Shield Tablet outscores the Snapdragon 805 MDP tablet from Qualcomm, but curiously falls behind the other two, lower clocked, -A15 based SoCs. Even Nvidia’s previous generation Tegra 4 SoC in the EVGA Tegra Note 7 posts a higher score. We brought this to Nvidia’s attention and its engineers are looking into this issue.
The Shield Tablet performs better in the Graphics test, scoring nearly 1.4x higher than its closest rival.
Here we see the Tegra K1 flex its 192 CUDA cores, offering between 2x-3x the performance of the Snapdragon 805 in second place.
Once again Tegra 4 posts a better score than Tegra K1. Nvidia’s engineers are investigating and it’s likely this is a software issue.
Based on these results, Tegra K1 must be “a neural net processor; a learning computer” sent back through time to destroy all of the other SoCs that could lead a rebellion in the post-apocalyptic future.
After the firmware update from Nvidia to address the CompuBenchRS bug, overall RenderScript performance is mixed. The Tegra K1 in the Shield Tablet still posts the best scores in the Graphics, Image Processing, and Throughput tests, but the margin of victory, while still impressive, is substantially less. In the Face Detection and Physics tests, the Shield Tablet falls behind the Tegra Note 7. Tegra K1 outmatches the Tegra 4 in every conceivable way, so it’s safe to blame software for this anomaly. Nvidia’s engineers are looking into this issue, so hopefully we’ll have a more definite answer, and maybe a software update, in the near future.
Brightness
Brightness (also known as white level) measurements are taken by recording the luminance output of each device displaying a full white pattern, with the device's brightness slider set to both minimum and maximum values.
The Shield Tablet takes a step backward from the Tegra Note 7 in maximum brightness. While not ideal for outdoor use, it’s still comparable to other tablets.
In order to make device comparison possible, the rest of our display measurements, along with our battery testing, are performed with the screen set to a standardized white level of 200 nits.
Black Level
Our black level measurement is the luminance output of a full black pattern after the luminance output of full white has been standardized to 200 nits.
The Shield Tablet’s black level is very low, even lower than the high-quality display in the iPad Air. This improves the contrast ratio and overall image quality.
Contrast Ratio
Contrast ratio is the difference between a full white pattern and a full black pattern.
Limited by its max brightness level, the Shield Tablet achieves a reasonable contrast ratio, falling just below the iPad Air.
Gamma
Gamma compensates for the linear brightness levels displayed by a screen, versus the nonlinear way our eyes perceive light. A gamma curve of 2.2 is what we optimally want to see, as a screen with a gamma less than 2.2 appears brighter and with less shadow detail, while a gamma larger than 2.2 displays heavy shadows with fewer highlights.
The Shield Tablet again falls short of the Tegra Note 7, deviating furthest from the ideal value of all the tablets in our chart.
Color Temperature
Color temperature is a measurement in Kelvin, which is used to describe how “warm” or “cool” a given display is. Ideally, as long as you're not viewing your device in direct sunlight, this should be in the 6500 range. Higher color temperatures result in a cool, bluish hue, while lower temperatures deliver a warm or reddish tone.
Color temperature for the Shield is spot-on, improving color accuracy.
Color Gamut
Our volume measurements are compared against both the sRGB and AdobeRGB color gamuts. A reading of 100 percent on sRGB and 72 percent on AdobeRGB is the optimal reading for viewing the vast majority of digital consumer content. A lower reading is typically accompanied by an overly red or yellow image, and a higher reading is usually too blue/green.
The backlight used in the Shield Tablet’s screen is not capable of covering the full sRGB color gamut, unable to even reach an 80% reading. This issue is most noticeable with reds and blues. In practical terms, there will be no color gradation beyond the 77.2% gamut coverage area. Rather than a smooth transition between color shades, you get a solid splotch of color. Apparently, Nvidia was willing to sacrifice some screen quality to hit its aggressive price point.
Basemark OS II Full (Anti-Detection)
The Basemark OS II battery test scores are derived by repeatedly running the devices until enough data has been collected to determine the drain rate of the device.
Basemark OS II primarily works the CPU, leaving most of the GPU powered down. In this benchmark, the Shield Tablet outscores the Tegra Note 7. Even though the Shield’s -A15 cores are running at a higher frequency, moving to the 28nm HPM process and updated revision-three cores nets more performance while using less power. This is even more impressive when we consider screen area and battery size scaling. All else being equal, the Shield Tablet’s larger screen and small increase in battery size means it should only get ~88% of the battery life of the Tegra Note 7, not 8% more.
The two Samsung tablets and the iPad Air are all ~10” devices with significantly larger batteries, skewing battery life results in their favor.
BatteryXPRT 2014
BatteryXPRT 2014 is a specialized battery testing application for Android devices that provides users with an "expected" Lifetime score, as well as an overall Performance score. The test has two variations: Network-Connected and Airplane Mode. It’s modeled in part after the MobileXPRT benchmark, which consists of ten real-world test scenarios encompassing various photo operations and encryption.
Airplane mode estimates battery life for a device with no Internet connectivity, and Network mode estimates battery life for a device connected to the Internet via Wi-Fi or cellular data connection.
This benchmark also primarily uses the CPU, but mixes in light GPU work. In Airplane mode, the Tegra Note 7 lasts just over one-half hour longer than the Shield Tablet, reversing the order from the Basemark OS II Battery test. It’s likely that the GPU is to blame, but we’ll need to see the results from GFXBench to confirm.
There’s a much more precipitous drop in battery life when turning Wi-Fi on. The two devices use different controllers, and the Broadcom chip in the Shield Tablet doesn’t appear to be as energy efficient. I’ve also noticed what I would consider excessive power drain during standby with Wi-Fi left on, which subjectively corroborates these results.
The Shield Tablet turns in a slightly better performance than the Tegra Note 7, but curiously falls behind the Galaxy Note 10.1 Wi-Fi even though they posted similar scores in MobileXPRT.
GFXBench 3.0 Corporate
GFXBench's battery test measures battery life and performance stability by logging frame and battery discharge rate as the on-screen T-Rex test runs for 30 consecutive iterations. The results are given in two scores: estimated battery life in minutes and the number of frames rendered on the slowest test run (to gauge if a device is throttling).
GFXBench heavily stresses the GPU, and we see the power penalty paid for Kepler’s exceptional performance. The Shield Tablet only lasts for 2.3 hours, similar to a gaming laptop. While battery life is good while the CPU is under load, your gaming session won’t last very long on battery power.
Although time playing games away from a power outlet may be limited, your frame rates won’t be. Looping through T-Rex 30 times shows no hint of thermal throttling.
Nvidia does provide a way to improve battery life with the Processor Mode selection from within Settings. There are three preset options ranging from max performance to max battery life. There’s also an option to switch between these presets automatically at a preset battery level.
Processor Mode settings from within the SHIELD Power Control
The utility also provides the ability to customize the settings. The number of CPU cores can be set to either two or four, and the peak CPU frequency is adjustable in 10% increments. The more intriguing setting is for limiting the maximum frame rate to 20, 30, 45 or 60FPS.
Options for customizing the power mode
Leaving all four CPU cores active at their top frequency, I set the frame rate limit to 30 and reran GFXBench 3.0. With about half as many frames to draw, battery life improved from 138 minutes (2.3 hours) to 315 minutes (5.25 hours), a 2.28x increase with playable performance. Adjusting this setting substantially increases battery life and makes the Shield Tablet more viable as a mobile gaming device.
Looking into the crystal ball, Nvidia saw a tablet that excelled at media consumption, productivity and mobile gaming, launching a quest that spawned the Tegra Note 7, a decent general-purpose tablet, and the Shield Portable, a potent handheld gaming device. With the experience points gained from these side quests, Nvidia reaches the end of its journey and delivers the Shield Tablet and Shield Controller, fulfilling the initial prophecy.
Powering the Shield Tablet is Nvidia’s Tegra K1 SoC. The Cortex-A15 cores, newly revised and manufactured on a 28nm process, are able to reach higher clock rates with lower power consumption, delivering excellent performance surpassed only by Apple’s Cyclone architecture.
But the real gem inside Tegra K1 is the Kepler-based GPU. The fact that Nvidia was able to take a desktop-class architecture and shrink its power envelope down to something that works in a handheld tablet is nothing short of amazing. Sure, it still uses too much power to be viable in a phone, and its battery life in a tablet isn’t stellar either. But the performance increase, upwards of 1.8x higher than the recently-released Adreno 420, is impressive.
With such a leap in performance, it appears the Tegra K1 will remain atop the benchmark charts well into 2015. The release of the iPhone 6 gives us our first look at Imagination’s latest PowerVR Series6XT GPU. The GX6450 variant in the iPhone doesn’t come close to matching Kepler’s performance. We’ll have to wait for the next iPad to see if Apple makes an A8X with better performance. Further out is Snapdragon 810, which should surface in the first half of 2015. Qualcomm expects the Adreno 430 to be around 30% faster than Adreno 420. Based on our benchmarks, this won’t be enough to beat Kepler. And by then, Nvidia will have moved on to Maxwell.
The Shield Tablet has an understated, stealthy appearance with good build quality. Although slightly larger and heavier than other 8” tablets, I didn’t find this to be an issue while actually using it.
The 8” screen is a reasonable compromise between portability, usability and quality. For a decent gaming experience, the tablet needs to be within close proximity for the title to feel immersive and for on-screen objects, especially text, to be discernible. Personally, I prefer the larger screen area offered by ~10” tablets, but the Shield Tablet at least uses the preferable 16:10 aspect ratio. Similar to screen size, panel quality is also a compromise, with other small form factor tablets offering higher pixel densities, peak brightness, and wider color gamuts. Fortunately, these shortcomings were rarely noticeable during use, at least by me.
The Shield Tablet’s front-facing stereo speakers are a nice feature even if they’re only average in sound quality. They do, however, offer enough spatial separation to give directional cues while gaming.
With so much emphasis on performance and gaming, it’s easy to overlook the included stylus. Nvidia’s DirectStylus 2 technology works extremely well. It’s precise, includes pressure sensitivity, there’s almost no input lag and the chisel tip stylus feels similar to using a pen. The handwriting recognition is also very accurate, and I like that all of the processing takes place on the tablet rather than in the cloud.
The allure of the Shield Controller arises from all of the extra features that help integrate it with the tablet. Integration with Google Now simplifies interaction with the tablet, and using the small touch pad or joystick-controlled mouse pointer improves screen navigation when the tablet is out of reach. It also includes the standard Android navigation buttons, which do double duty for in-game navigation. Tight integration with the Shield Hub app severs any remaining dependency on the touchscreen interface.
The Shield Tablet’s software echoes the clean and efficient hardware design. It’s simply stock Android with a few Nvidia apps and flourishes to integrate the extra functions. The Shield Hub app uses a simple interface and does a decent job of making the Shield-specific features accessible from one place. It would be nice to have more control over selecting which apps appear inside the Shield Hub, though.
Features like the DirectStylus Launcher and the additional buttons added to the Android navigation bar help make the stylus feel like an integral part of the device. However, there needs to be an easier method for toggling between the keyboard and handwriting modes.
What really differentiates the Shield Tablet from its peers are the games and gaming features. There’s already a diverse Android gaming ecosystem with several titles using enhanced visuals that take advantage of Tegra K1’s additional capabilities. Features like Nvidia Grid and GameStream grant access to games stored in the cloud and on your PC (assuming you have a decent router and an Nvidia graphics card). I found both of these features to work well during testing, encountering a few game controller compatibility issues with older PC titles.
I did experience some minor issues with Wi-Fi connectivity. The Shield Tablet would consistently fail to reconnect to Wi-Fi after toggling airplane mode off and on. Turning Wi-Fi off and on would get it to reconnect. I also encountered problems pairing the Shield Controller with the tablet on several occasions. Again, toggling Wi-Fi off and on fixed the problem. Hopefully, this is just a driver issue that Nvidia will ameliorate in the near future.
At $299 for the Wi-Fi-only model, the Shield Tablet is a compelling buy, even for someone who doesn’t care about gaming. Adding in the cost for the Shield Controller and cover brings the total Shield package up to nearly $400. For that price you can buy an Xbox One or PS4, although they aren’t portable solutions. If you’re only interested in streaming PC games to an HDTV in another room, you could get a low-end laptop and use Steam’s In-Home Streaming feature. The Shield Tablet only makes sense for someone who actually needs a tablet; the stylus and portable gaming capabilities seal the deal.
A bevy of combatants and fierce competition have turned the market for small form factor tablets into a war zone, but excellent performance and unique, well-implemented features give the Shield Tablet an edge in battle.












































