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Apple's iPad 3, Part 1: The Complete Retina Display And A5X Review
By , Alan Dang,
1. The New iPad: Let's Get Technical

This is in Bakersfield, CA, mind you.This is in Bakersfield, CA, mind you.

On Friday, most people in the world awoke and went about their normal routines. But a fevered few—the truly hardcore believers—instead abandoned their plans, rescheduled meetings, skipped classes, called-in sick, and joined the mad rush to buy the new iPad 3. Was it worth the trouble? Well, that depends on who you ask. The iPad 3 is a near duplicate in looks and size of its predecessor (which is why Gizmodo was able to fool a few into believing an iPad 2 was an iPad 3), causing some to question the hype. Yet, for those who really know what they're shopping for, the iPad 3 delivers.

The iPad 3 is slightly heavier than its predecessor. On our shipping scale, the actual weight comes out to 660 grams, or 1.45 lb. That's 10% heavier than the iPad 2 3G (600 grams/1.31 lb.), reminding us that holding the original iPad became tiresome after a few hours. We're not pleased with the added weight, but examining this device's physical attributes will have to wait for a more in-depth review to follow.

Apple iPad 3: Features Explained

In the meantime, let's cut the lights and roll the highlight reel. The video above sums up everything. Unveiled by Apple a couple of weeks back, the iPad 3 has four key selling points over the iPad 2:

  • A new "HD" Retina Display
  • Improved graphics performance
  • 5 MP rear camera
  • 4G LTE mobile broadband networking


Personally, the relatively low screen resolution of previous tablets has always been a bit of a turn-off. However, the iPad 3 display is the exact opposite, delivering a whopping 2048x1536 resolution and 264 pixels per inch on the same 9.7" screen as before. The result: an exceptionally crisp display, particularly well-suited for viewing pictures and watching movies. The display is unquestionably superior—but how much so? Let's dig deeper.

2. Why We Need (Or At Least Want) HD Tablets...

Tablets are often regarded as cheap notebook replacements, and we often excuse their low-resolution displays as a result. However, this expectation may also have delayed significant improvements in tablet display resolution and image quality.

For example, the iPad 2 had a screen resolution of 1024x768 on a 9.7" screen, resulting in 132 pixels per inch. Samsung's gorgeous SuperPLS display is only slightly better; 1280x800 resolution on a 10.1" display results in 149 pixels per inch.

Why does this matter? A screen's native resolution directly corresponds to its ability to display fine detail. Recall a time when 20" CRT monitors were limited to 1024x768. The output was less than impressive on a screen that large. But later 20" screens supporting higher resolutions looked far better. Apple is the first to take this resolution leap, if you will, in the tablet space.

At 2048x1536, the iPad 3's 9.7" screen yields 264 pixels per inch, which better than almost every desktop display. A22" monitor running at 1080p has a pixel density close to 100 ppi. In fact, iPad 3 displays such fine detail that it is near the 286 ppi limit of what a human eye can resolve under ideal conditions. 

Model
iPad 2
iPad 3
Galaxy Tab 10.1
Transformer (Original)
Screen Size
9.7"
9.7"10.1"
10.1"
Aspect Ratio
4:3
4:3
16:9
16:9
Native Resolution
1024x768
2048x1536
1280x800
1280x800
Pixels Per Inch
132
264
149
149


In order to give you an idea of how much more detail to expect, check out the side-by-side comparison of the "Maps" icon on the home screen:

iPad 2iPad 2iPad 3iPad 3

It's startlingly easy to see the difference. The small red way-point and individual roads are incredibly pixelated on the iPad 2 when you zoom in close.

iPad 2iPad 2iPad 3iPad 3

You're never going to magnify the screen like this in the real-world. However, the difference is still pretty clear from a foot away. Smaller pixels help make edges and borders appear sharp and clear, and help define colors more accurately. You can see all three effects quite easily in the side-by-side comparisons. The interstate sign is very sharply defined, and the blue looks more vivid. But are smaller pixels the only improvement made to the iPad 3's display? Let's break out our microscope.

3. When It Comes To Subpixels, Smaller Is Better

Understanding the nature of a display's potential requires an inspection of the size, shape, and arrangement of individual subpixels. This lets you identify the type of LCD panel and calculate the smallest detail it's capable of rendering. If you're already familiar with our tablet and smartphone coverage, then you know we apply this level of analysis to every mobile device that passes through our lab.

Focusing closer with our lab microscope, we learn two important pieces of information.

First, Apple retains the familiar S-IPS technology on its new Retina display. We know this because the subpixel shape reveals a Samsung IPS design, which makes sense considering the previous iPad displays were also manufactured by Samsung. In short, you'll enjoy the same wide viewing angles on the iPad 3 as its predecessor.

Second, the relatively small size of each subpixel implies a significantly improved color palette. Since every pixel contains three subpixels (red, green, and blue), more pixels allows you to create a wider variety of colors. For example, a bluish-green can be created by turning on the blue and green subpixels, while turning off the red subpixels. The relative bluish tint is achieved by having a brighter blue LED and slightly dimming green. You can only so far, though, because pixels have a fixed range of brightness.

On the iPad 3, specifically, each subpixel measures approximately 30x65 microns. So, you can fit approximately four iPad 3 pixels into the space of a single iPad 2 pixel. Thus, a truer bluish-green hue is possible by turning on four blue subpixels and two green subpixels.

Apple iPad 3: Retina Display, Explained

The problem with small pixels is that electrical leakage requires spacing to prevent color blending. Apple overcomes this challenge by cleverly elevating the subpixels off the base LCD circuitry. Though, even with our laboratory-grade microscope tilted at a 30o angle, combined with strong lighting, the gap is still difficult to see. The video above summarizes the technology's details.

4. Better Color And Adobe RGB Performance

Most people will find that the Retina display delivers more spectacular colors, as it renders nearly 66% of the Adobe RGB1998 color gamut—nearly a 35% improvement over the iPad 2. Just by looking at the 2D LUV color map, we can see that the improvement is most noticeable in images containing rich reds and blues. (Updated: Here's a more detailed gamut map including Galaxy Tab 10.1.)


The iPad 3’s Retina display matches the brightness of other spectacular screens, such as the Transfomer Prime's SuperIPS, but is capable of rendering more colors. Apple clearly puts the iPad 3’s image quality on center stage, and the results speak for themselves.

The 2.4 gamma is remarkably close to the ideal 2.2, which means photographers should be pleased that mid-tones appear “just right” (not too pale, not too bright).


iPad 2
iPad 3
Galaxy Tab 10.1
Transformer Prime (SuperIPS Off)
Gamut of Adobe RGB 1998
49.9%
66%
62.8%
40.2%
Gamma
2.34
2.4
1.82
1.76
Max. Brightness (nits)
379.1
403.6
360.4
409.9
Color Temperature
7100 K
6800 K
8900 K
6500 K
Resolution
1024x768
2048x1536
1280x800
1280x800
Pixels per inch
132
264
149
149
Contrast Ratio
758.2
1009.5
1122.9
819.8
5. Safari Downsamples Your Images, No HD

Web-browsing on any iOS-based device is often a less-than-satisfactory experience. Specifically, when it comes to pictures and images, the mobile version of Safari automatically downsamples any image when it hits the 1024-pixel limit. When an image exceeds that threshold, it's downsampled by every nth pixel, such that n is the smallest divisor that yields an image less than or equal to 1024 pixels.

SafariSafari

SafariSafari

Apple does this to optimize rendering speed and improve overall browsing performance. The behavior is also inherent to older iPhones and iPads. However, the implication on an iPad 3 is more serious, especially if you are a photography enthusiast. It means that you can't view HD-quality online pictures from sites like Flickr, Smugmug, or Zenfolio in their true native glory because the iPad 3 will reduce the viewable resolution. This also happens if you try to view the JPEG file directly using the iPad 3’s Safari Web browser.

Pictures Hosted On Website, From Camera
Actual Resolution
Rendered On iOS' Safari
Phase One IQ180
80.1 Megapixels
(10328 x 7760)
1.25 Megapixels
(1291 x 970)
Nikon D800
36.2 Megapixels
(7360 x 4912)
1.45 Megapixels
(1472 x 982)
Canon 5D Mark III
22.3 Megapixels
(5760 x 3840)
1.38 Megapixels
(1440 x 960)
Canon 7D / 60D / T3i / T2i
18.0 Megapixels
(5184 x3456)
1.12 Megapixels
(1296 x 864)
Canon 50D / T1i
15.1 Megapixels
(4752x3168)
0.94 Megapixels
(1188 x 792)
Canon Rebel T3 / 1100D
12.2 Megapixels
(4272 x 2848)
0.76 Megapixels
(1068 x 712)


As far as we have been able to determine, photographers have to import photos directly into iPhoto if they want their images displayed at a higher resolution. (Update, Andrew: We'll cover this in part two, but there is an exception that was originally ignored. It is possible to view the native picture on the iPad 3, but you have select the image in Safari and save to iPhoto. Try pictures at Canon's 5D MK3 Sample Gallery.) In theory, Apple should be able to fix this problem by allowing users the option to disable resizing in Safari's settings panel.

iPhotoiPhoto

iPhotoiPhoto

6. CPU And GPU Performance: All About Graphics

The CPU: A9 Flavor

Apple A5X, Source: iFixitApple A5X, Source: iFixit

The iPad 3 features a new SoC, the A5X. Like the preceding A5, it features a dual-core A9 ARM processor clocked at 1 GHz. We've covered the architecture of the A9 in the past, so we won't revisit the details, but for those interested in a deeper discussion, you can head back to our original A5 coverage.


Apple A4 (iPad)
Apple A5 (iPad 2)
Apple A5X
Fab Node
45 nm
45 nm
45 nm
Processor
1 GHz ARM Cortex-A8 (single-core)
1 GHz ARM Cortex-A9 (dual-core)
Memory
256 MB LP-DDR
512 MB LP-DDR2
1 GB LP-DDR2
Graphics
PowerVR SGX535 (single-core)PowerVR SGX543MP2 (dual-core)PowerVR SGX543MP4 (quad-core)
L1 Cache
(Instruction/Data)
32 KB / 32 KB
32 KB / 32 KB
L2 Cache640 KB
1 MB


On paper, there's really nothing to suggest improved CPU performance from the A5X. There's no change in cache size, and though there's apparently twice as much on-die RAM, it has no impact on raw computational horsepower. The new A5X seems intended to help improve multitasking support and enable a beefier graphics engine, so our GeekBench results are, not surprisingly, largely unchanged.

GeekBench v2.2.7 Results
iPad 2
iPad 3
Dell Mini 1012
LePan II
Transformer Prime
CPU
Apple A5
Apple A5X
Atom N450
APQ8060
Tegra 3
Architecture
Dual-core A9
Dual-core A9
Single-Core Atom
Dual-core ScorpionQuad-core A9
Speed
1 GHz1 GHz1.66 GHz1.2 GHz1.4 GHz
Overall
764
760
917
649
1194
Integer
691
687
910
709
1781
Floating Point
921
920
762
943
1781
Memory
830
825
1105
362
1091


The GPU: Double Your Pleasure

One aspect of Apple's A5X truly shines: graphics performance. Since an ultra-high-resolution display is the iPad 3’s core selling point, Apple's A5X features a significantly more powerful graphics engine optimized for the Retina display. This increases gaming potential by a lot. In fact, Apple claims the iPad 3 offers double the graphics performance of the iPad 2. How is this possible?

GPU System-on-Chip
PowerVR SGX 535
(Apple A4)
PowerVR SGX 543
(Apple A5/A5X)
SIMD
USSE
USSE2
Pipelines
2
4
TMUs
2
2
Bus Width (in bits)
64
64
Triangle rate @ 200 MHz
14 MTriangles/s35 MTriangles/s


Apple still employs Imagination's PowerVR SGX543 architecture, used in the iPad 2. But whereas the iPad 2 was limited to a dual-core implementation (SGX543MP2), the iPad 3’s A5X sports a muscular quad-core GPU (SGX543MP4). Incidentally, Sony's PlayStation Vita also uses a the SGX543MP4.

Apple A5X, Source: UBMApple A5X, Source: UBM

That hardware change is easy to spot when you inspect the A5X's die. In the annotated layout above, you can quite clearly identify each of the four GPU cores. It also appears that RAM accesses has changed to accommodate the increased need for bandwidth. The A5 employed a pair of memory interfaces; UBM's image above suggests four on the A5X. To get a more illustrative story, though, let's look at GLBenchmark.

GLBenchmark 2.1.2
*native resolution
iPad 2
iPad 3
Kindle Fire
LePan II
Transformer Prime
GPU
PowerVR SGX543MP2
PowerVR SGX543MP4PowerVR
SGX540
Adreno 220
Tegra 3 (ULP GeForce)
Egypt Standard*
6661 frames (59 FPS)
6709 frames (59 FPS)
2847 frames (25 FPS)
3485 frames (31 FPS)
5388 frames (48 FPS)
Egypt Fixed Time Step*
47.598 s (59 FPS)
47.261 s (60 FPS)
116.138 s
112.659 s (25 FPS)
69.055 s (41 FPS)
Egypt Off Screen (720p)
10 146 frames (90 FPS)
15 663 frames (139 FPS)
2516 frames (22 FPS)
3603 frames (32 FPS)
6496 (58 FPS)
Pro Standard*
2962 frames (59 FPS)
2975 frames (60 FPS)
1981 frames (39 FPS)
2140 frames (43 FPS)
2726 frames (54 FPS)
Pro Fixed Time Step*
20.868 s (60 FPS)
20.857 s (60 FPS)
34.658 s
31.982 s (39 FPS)
24.189 s (52 FPS)
Pro Off Screen (720p)
7352 frames (147 FPS)
12546 frames (251 FPS)
2277 frames (46 FPS)
2332 frames (47 FPS)
3717 frames (74 FPS)


According to the standard tests in GLBenchmark, nearly identical scores on the iPad 2 and iPad 3 imply similar perceived overall gaming performance. That doesn't seem like it'd blow you away, but it's actually pretty amazing when you consider the iPad 3's 2048x1536 native resolution. Comparing these two devices at their native resolutions is by no means an apples-to-apples match-up. But it is cool that the iPad 3’s A5X delivers the same performance with four GPU cores at 2048x1536 resolution as the iPad 2’s A5 with two cores at 1024x768.

Comparing the raw graphics performance of each hardware implementation using GLBenchmark's off-screen tests reveals that the A5X delivers about 1.5-2x more performance than the A5. More interestingly, the Tegra 3-based Transformer Prime actually falls behind the older iPad 2. In fact, when we compare the Transformer Prime to the iPad 3, we see a two- to three-fold jump in performance favoring Apple's tablet.

GLBenchmark 2.1.2
iPad 2
iPad 3
Triangle Test
65.0 Mtriangles/sec
129.2 Mtriangles/sec
Triangle Texture Test
58.0 Mtriangles/sec
120.8 Mtriangles/sec
Triangle Texture Test, Vertex Lit
45.6 Mtriangles/sec
93.6 Mtriangles/sec
Triangle Texture Test, Fragment Lit
43.5 triangles/sec
92.3 Mtriangles/sec


According to Imagination, its PowerVR tile-based deferred rendering architecture is highly dependent on memory bandwidth, which means there's a direct relationship between throughput and triangle rates. Based on our results from the iPad 3, it's pretty clear that graphics performance improvements are related both to a more complex GPU and greater bandwidth. The iPad 2 and iPad 3 seemingly both employ 800 MT/s LP-DDR2 by way of a dual-channel configuration. However, the iPad 3 utilizes four 32-bit memory interfaces, which is two more than its predecessor.

7. The New iPad: The Best-Looking, With Caveats

Without question, the iPad 3’s Retina display is impressive. Improvements made to its subpixel structure produce better display detail and higher color fidelity, resulting in the first consumer tablet display able to satisfy most demanding technologists. In fact, the iPad 3’s image quality is so much better that it usurps our previous favorite, the Galaxy Tab 10.1. Even if you just go by the numbers (our color gamut benchmarks), the iPad 3 is the winner.

Apple effectively doubled iPad 3's graphics horsepower, a move that was necessary in order to handle a higher native resolution. In our initial assessment, playing games like Infinity Blade, Real Racing HD, and RipTide feel roughly similar on the iPad 3 as they did on the iPad 2, though.

Our one complaint, right off the bat, is that iOS' Web browser, Safari, does not display high-resolution pictures in their native format. There appears to be no way to disable forced downsampling, and this will disappoint—nay, infuriate—many serious photographers and graphic artists when they discover the iPad 3’s awesome screen is not so awesome when it comes to viewing online HD content. Fortunately, it's possible to view pictures in their native resolution by saving from Safari to iPhoto. Hopefully, this situation improves with Apple's next iOS upgrade.

Infinity Blade on iPad 3Infinity Blade on iPad 3

As you might expect, playing games that were designed to run on an iPad 2 happens smoothly on an iPad 3. What you shouldn't expect, however, is that existing titles will hit you with significantly more fidelity, aside from the increased pixel density attributable to the display itself. We need titles with higher-quality textures and more optimizations for the iPad 3's upgraded graphics capability. It'll likely take developers some time to figure out how to best balance the more powerful hardware, higher resolution, and detail settings on games written for Apple's latest and greatest.

In the meantime, the iPad 3 is your best (and only) choice if you want a tablet with an awesome high-resolution display. Tests continue in our lab, and our next story will cover battery life, 4G LTE mobile broadband performance, and a more comprehensive analysis of the iPad 3's gaming experience.