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GPU Performance: Nvidia Tegra 2

Asus Eee Pad Transformer TF101: A Tablet In Disguise
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As we’ve mentioned in the past, mobile devices like smartphones and tablets use what’s known as a system-on-chip (SoC). This integrates the processor, GPU, RAM, and several other subsystems onto single device. Since all of those components sit next to each other on the same chip, there is greater efficiency in data transfers, while reducing the amount of space consumed on the PCB.


Apple A4 (iPad)
Apple A5 (iPad 2)
Tegra 2 (Xoom/Iconia A500/Eee Pad Transformer)
Processor
1 GHz ARM Cortex-A8 (single-core)
1 GHz ARM Cortex-A9 (dual-core)
1 GHz ARM Cortex-A9 (dual-core)
Memory
256 MB 333 MHz LP-DDR (single-channel)
512 MB 1066 MHz LP-DDR2 (dual-channel)
1 GB 667 MHz LP-DDR2 (single-channel)
Graphics
PowerVR SGX535 (single-core)PowerVR SGX545MP2 (dual-core)ULP GeForce (single-core)
L1 Cache
(Instruction/Data)
32 KB / 32 KB
32 KB / 32 KB
32 KB / 32 KB
L2 Cache640 KB
1 MB1 MB


Tegra is Nvidia’s SoC brand, and it represents the company’s effort to tap into the mobile market beyond its desktop-derived GeForce graphics processors. For those unfamiliar with Tegra 2, read page eight of our Motorola Xoom review for a full discussion on GPU architecture. On the CPU side, Tegra 2 shares the same dual-core Cortex-A9, which is a substantial boost from Cortex-A8 seen in the first-generation iPad. Check out Apple's iPad 2 Review: Tom's Goes Down The Tablet Rabbit Hole for a full discussion of Cortex-A9 performance.

While we've already covered Tegra 2, it's important to examine the graphics performance of each tablet. Sy Choudhury, director of product management at Qualcomm, states, "There is a misconception that the same processor and operating system gives the same performance." We run into that issue every time we review a tablet. Why is it wrong to expect the same performance from all Honeycomb-based Tegra 2 tablets? Hardware vendors get access to the same optimizations from the SoC developer, but not all of the software-based tweaks are enabled by OEMs.

GPU (System-on-Chip)
PowerVR SGX 535
(Apple A4)
PowerVR SGX 543
(Apple A5)
ULP GeForce (Tegra 2)
SIMD
USSE
USSE2
Core
Pipelines
2 (unified)
4 (unified)
8 (4 pixel / 4 vertex)
TMUs
2
2
2
Bus Width (bit)
64
64
32
Triangle rate @ 200 MHz
14 MTriangles/s35 MTriangles/s?


The ULP GeForce has a maximum operating frequency of 300 MHz, but device vendors can tweak this setting to save on power. Nvidia provides less information on the Tegra 2 than it does for its desktop GPUs, so it’s best to move on to benchmarks. As in our iPad 2 review, we're turning to GLBenchmark 2.0.

In terms of frames rendered in a set period of time, the Xoom, Iconia A500, and Transformer offer more performance than the original iPad. But all three Tegra 2-based tablets still fall short of the iPad 2. Interestingly, the Transformer performs worse than the A500 with Honeycomb 3.1. Once we update to 3.2, Asus' tablet jumps ahead by more than 20%.

There is a direct relationship between memory bandwidth and triangle rates in the A4 and A5's PowerVR GPUs, due to their tile-based deferred rendering architecture. But PowerVR GPUs operate differently than what we're used to seeing on the desktop. Tegra 2, on the other hand, employs a more traditional z-buffered rendering architecture. As such, it's only possible to compare the triangle rates of competing Tegra 2-based tablets.

If you want to go into more depth than what is provided here, the full results of GLBenchmark 2.0 have been posted on Google Docs.

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  • 4 Hide
    americanherosandwich , September 13, 2011 4:28 AM
    If only some of them sold for $99... but a chance to win one of four for free = just plain awesomeness!
  • 0 Hide
    compton , September 13, 2011 4:42 AM
    Having recently tried the Transformer in person, I can say that it doesn't feel cheap and the novelty of the docking system could be awesome in future iterations. But as I recently found out with my $99 HP TouchPad, tablets have a long way to go in some areas. In the TouchPad's case, many of it's problems seem to go away when overclocking it's processor from 1.2Ghz to 1.8Ghz +. Of course, it's battery life is already less than compelling so you don't really notice the higher power usage. Like so much in life, better and faster hardware makes all the difference. Higher clock speed overcomes many of the problems HP could have ironed out had they given WebOS more time.

    The Transformer is a not-insignificant step forward for Android tablets. As an optimist, I believe the next iteration will be pretty damn good. But like the TouchPad, who knows how much longer it's going to be around?
  • 3 Hide
    Dangerous Beans , September 13, 2011 4:43 AM
    americanherosandwichIf only some of them sold for $99... but a chance to win one of four for free = just plain awesomeness!


    Yeah, if you are American. Hey Toms, how about you find some way to only display the comp if the reader is on an American IP address.
    Or better yet, find a way to let us enter.

    What is the point of a 32gb model when the tablets has a micro sd slot? I can get 2 32gb mSD cards for the extra $100 bucks.
  • 1 Hide
    clonazepam , September 13, 2011 6:00 AM
    I went to the verizon store to get help choosing some decent headphones for my bionic. While I waited for him to go in the back of the store and get a few models, I started playing pinball on the galaxy tab 10.1. When he came back there was that brief moment I couldn't decide to keep playing and ignore him, or set it down. win win here.
  • 1 Hide
    clonazepam , September 13, 2011 6:03 AM
    Dangerous BeansYeah, if you are American. Hey Toms, how about you find some way to only display the comp if the reader is on an American IP address. Or better yet, find a way to let us enter. What is the point of a 32gb model when the tablets has a micro sd slot? I can get 2 32gb mSD cards for the extra $100 bucks.


    They could do international possibly, if any international persons agreed to help pay shipping (I bet). A UK site I won't name allows international entries and lets them know up front they'd try to work with you on the shipping costs, etc.

    Wanted to add. I bought a transformer and dock for my mother. She's in her 60s and loves it. She takes it to work, to the coffee shop. I set it up for her, my first time with Android, and it definitely has its uses.
  • 0 Hide
    Geef , September 13, 2011 6:42 AM
    Well the first thing I think of when I'm looking at a tablet is NOT watching a movie in the park or playing around like most commercials show. I actually think of when I get up off the computer chair to head to the toilet. I don't read the newspaper here so where else am I gonna get my up to date info? Only bad thing I can think of for that is needing to wash hands and Tablet. :p 
  • 0 Hide
    ps3hacker12 , September 13, 2011 7:17 AM
    BTW WARNING ITS A US ONLY COMPETITION : (
  • 0 Hide
    siege_templar , September 13, 2011 8:48 AM
    i am so sad, i cant enter comp due to:
    under 18
    and i live in aus :( 
    isnt tomshardware from germany?
  • 0 Hide
    anonme , September 13, 2011 9:27 AM
    On the other side of the screen argument it seems to be one of the few that does not need closed curtains.
    Heavens forbid, it sounds decent outdoors too thoug OLED is probably better.
  • -5 Hide
    anonme , September 13, 2011 9:27 AM
    On the other side of the screen argument it seems to be one of the few that does not need closed curtains.
    Heavens forbid, it sounds decent outdoors too thoug OLED is probably better.
  • -5 Hide
    anonme , September 13, 2011 9:27 AM
    On the other side of the screen argument it seems to be one of the few that does not need closed curtains.
    Heavens forbid, it sounds decent outdoors too thoug OLED is probably better.
  • 0 Hide
    Device Unknown , September 13, 2011 10:32 AM
    I have been a loyal follower since Thomas first had his site up. I remember reading your BIO, you had this pic of you up, and how amazed I was at your dedication from leaving the medical field as a Doctor to taking technology to new heights with overclocking etc. Thomas always impressed me and I could not be happier with his success in life and with Thomshardware. Been a long road, many years. (I overclocked my first 486 DX2-66 thanks to you)
    I have entered every contest I could, haven't won, but will always be a loyal follower!
    To the other posters about this being US only. It's not the shipping costs, it's the laws and regulations on sending US hardware to other countries. Not impossible but too much of a bureaucratic pain to try to send anywhere in the world.
  • 0 Hide
    Lyrick , September 13, 2011 12:50 PM
    Is there any way to test the OpenGl and other video benchmarks at the same resolution? Maybe through the use of a video out or downscaling the other products to apple resolution. It seems unfair to bench Apple products at 1024 x 768 and others such as the asus transformer at higher resolutions like 1280 x 800.
  • 2 Hide
    cknobman , September 13, 2011 1:50 PM
    While I understand the position of the articles author I think the ASUS Transformer fills its niche perfectly.

    I purchased my ASUS Transformer for only $299(that was my ceiling price for a tablet) on sale and did so knowing that this tablet was not meant to replace my notebook for content creation.

    I can say since my wife and I have owned this tablet (2 months now) we have only used our laptop 1 time (and it was very frustrating using it that 1 time). The tablet is the perfect utility for doing couch surfing, social networking, light casual gaming, and QUICK information lookup on the web (which is what we do most often). This tablet was the perfect escape from the 5+ minute bootup and 3 minute shutdown of our laptop for situations where all we wanted was to hop on the internet and look up some information real quick.

    We never turn the tablet completely off and the touch of the power button and it is ready to go instantly. The battery will literally last an entire day (even with heavy usage), we stream netflix, and stream movies-pictures-videos straight from my server.

    All in all we are 100% happy with our Asus transformer and dont regret the purchase in any way.
  • 0 Hide
    Au_equus , September 13, 2011 2:11 PM
    the tf 2 iteration will be priced at tf 1's current price levels with the tf 1 price dropping. a tegra 3 tablet for $400 in november? it'll beat out the competition for the next few months, that is if it is no longer delayed
  • 2 Hide
    jabliese , September 13, 2011 2:48 PM
    No stupid facebook, hooray!
  • 0 Hide
    Anonymous , September 13, 2011 3:31 PM
    the newest version of Glbenchmark has an off screen test at 720p which can be used to compare devices with different resolutions
  • 1 Hide
    JohnA , September 13, 2011 3:50 PM
    Got to play with an Ipad 2 for a good while this weekend. Can't see a good reason to pick this over it, unless price is your only concern. The Ipad beats it in every other way.
  • -2 Hide
    megamanx00 , September 13, 2011 5:26 PM
    I have the 16GB version and I like it. It's great as a tablet, but it's not replacing my i7 laptop for doing any kind of work :D 
  • 2 Hide
    randomstar , September 13, 2011 6:20 PM
    I bought a 10 inch tablet, but I just could not get away from needing to be able to do remote desktops and handle office doc, outlook. so i bought the Acer W500 - and could not be happier. I had purchased the A500 and took it back. note- it has a dock base similar to this one, but as it is a generic USB connection, you can use a USB extension cable to get keyboard to work from a vehicle mount!
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