Yesterday Apple unveiled its third generation iPad, simply called the new iPad, at an event in San Francisco. The form factor remains mostly unchanged with a 9.7-inch display, however the new device is thicker at 9.4mm vs. 8.8mm for its predecessor. The added thickness was necessary to support the iPad's new 2048 x 1536 Retina Display.

Tablet Specification Comparison
  ASUS Transformer Pad Infinity Apple's new iPad (2012) Apple iPad 2
Dimensions 263 x 180.8 x 8.5mm 241.2 x 185.7 x 9.4mm 241.2 x 185.7 x 8.8mm
Display 10.1-inch 1920 x 1200 Super IPS+ 9.7-inch 2048 x 1536 IPS 9.7-inch 1024 x 768 IPS
Weight (WiFi) 586g 652g 601g
Weight (4G LTE) 586g 662g 601g
Processor (WiFi)

1.6GHz NVIDIA Tegra 3 T33 (4 x Cortex A9)

Apple A5X (2 x Cortex A9, PowerVR SGX 543MP4)

1GHz Apple A5 (2 x Cortex A9, PowerVR SGX543MP2)
Processor (4G LTE) 1.5GHz Qualcomm Snapdragon S4 MSM8960 (2 x Krait)

Apple A5X (2 x Cortex A9, PowerVR SGX 543MP4)

1GHz Apple A5 (2 x Cortex A9, PowerVR SGX543MP2)
Connectivity WiFi , Optional 4G LTE WiFi , Optional 4G LTE WiFi , Optional 3G
Memory 1GB 1GB 512MB
Storage 16GB - 64GB 16GB - 64GB 16GB
Battery 25Whr 42.5Whr 25Whr
Pricing $599 - $799 est $499 - $829 $399, $529

Driving the new display is Apple's A5X SoC. Apple hasn't been too specific about what's inside the A5X other than to say it features "quad-core graphics". Upon further prodding Apple did confirm that there are two CPU cores inside the SoC. It's safe to assume that there are still a pair of Cortex A9s in the A5X but now paired with a PowerVR SGX543MP4 instead of the 543MP2 used in the iPad 2. The chart below gives us an indication of the performance Apple expects to see from the A5X's GPU vs what's in the A5:

Apple ran the PowerVR SGX 543MP2 in its A5 SoC at around 250MHz, which puts it at 16 GFLOPS of peak theoretical compute horsepower. NVIDIA claims the GPU in Tegra 3 is clocked higher than Tegra 2, which was around 300MHz. In practice, Tegra 3 GPU clocks range from 333MHz on the low end for smartphones and reach as high as 500MHz on the high end for tablets. If we assume a 333MHz GPU clock in Tegra 3, that puts NVIDIA at roughly 8 GFLOPS, which rationalizes the 2x advantage Apple claims in the chart above. The real world performance gap isn't anywhere near that large of course - particularly if you run on a device with a ~500MHz GPU clock (12 GFLOPS):

GLBenchmark 2.1.1 - Egypt - Offscreen (720p)

GLBenchmark 2.1.1's Egypt offscreen test pegs the PowerVR SGX 543MP2 advantage at just over 30%, at least at 1280 x 720. Based on the raw FP numbers for a 500MHz Tegra 3 GPU vs. a 250MHz PowerVR SGX 543MP2, around a 30% performance advantage is what you'd expect from a mostly compute limited workload. It's possible that the gap could grow at higher resolutions or with a different workload. For example, look at the older GLBenchmark PRO results and you will see a 2x gap in graphics performance:

GLBenchmark 2.1.1 - PRO - Offscreen (720p)

For most real world gaming workloads I do believe that the A5 is faster than Tegra 3, but the advantage is unlikely to be 2x at non-retinadisplay resolutions. The same applies to the A5X vs. Tegra 3 comparison. I fully expect there to be a significant performance gap at the same resolution, but I doubt it is 4x in a game.

Mobile SoC GPU Comparison
  Apple A4 Apple A5 Apple A5X Tegra 3 (max) Tegra 3 (min) Intel Z2580
GPU PowerVR SGX 535 PowerVR SGX 543MP2 PowerVR SGX 543MP4 GeForce GeForce PowerVR SGX 544MP2
MADs per Clock 4 32 64 12 12 32
Clock Speed 250MHz 250MHz 250MHz 500MHz 333MHz 533MHz
Peak Compute 2.0 GFLOPS 16.0 GFLOPS 32.0 GFLOPS 12.0 GFLOPS 8.0 GFLOPS 34.1 GFLOPS

The A5X doubles GPU execution resources compared to the A5. Imagination Technologies' PowerVR SGX 543 is modular - you can expand by simply increasing "core" count. Apple tells us all we need to know about clock speed in the chart above: with 2x the execution resources and 2x the performance of the A5, Apple hasn't changed the GPU clock of the A5X.

Assuming perfect scaling, I'd expect around a 2x performance gain over Tegra 3 in GLBenchmark (Egypt) at 720p. Again, not 4x but at the same time, hardly insignificant. It can take multiple generations of GPUs to deliver that sort of a performance advantage at a similar price point. Granted Apple has no problems eating the cost of a larger, more expensive die, but that doesn't change the fact that the GPU advantage Apple will hold thanks to the A5X is generational.

I'd also point out that the theoretical GPU performance of the A5X is identical to what Intel is promising with its Atom Z2580 SoC. Apple arrives there with four SGX 543 cores, while Intel gets there with two SGX 544 cores running at ~2x the frequency (533MHz vs. 250MHz).

With the new iPad's Retina Display delivering 4x the pixels of the iPad 2, a 2x increase in GPU horsepower isn't enough to maintain performance. If you remember back to our iPad 2 review however, the PowerVR SGX 543MP2 used in it was largely overkill for the 1024 x 768 display. It's likely that a 4x increase in GPU horsepower wasn't necessary to deliver a similar experience on games. Also keep in mind that memory bandwidth limitations will keep many titles from running at the new iPad's native resolution. Remember that we need huge GPUs with 100s of GB/s of memory bandwidth to deliver a high frame rate on 3 - 4MP PC displays. I'd expect many games to render at lower resolutions and possibly scale up to fit the panel.

What About the Display?

Performance specs aside, the iPad's Retina Display does look amazing. The 1024 x 768 panel in the older models was simply getting long in the tooth and the Retina Display ensures Apple won't need to increase screen resolution for a very long time. Apple also increased color gamut by 44% with the panel, but the increase in resolution alone is worth the upgrade for anyone who spends a lot of time reading on their iPad. The photos below give you an idea of just how sharp text and graphics are on the new display compared to its predecessor (iPad 2, left vs. new iPad, right):

The improvement is dramatic in these macro shots but I do believe that it's just as significant in normal use. 

Apple continues to invest heavily in the aspects of its devices that users interact with the most frequently. Spending a significant amount of money on the display makes a lot of sense. Kudos to Apple for pushing the industry forward here. The only downside is supply of these greater-than-HD panels is apparently very limited as a result of Apple buying up most of the production from as many as three different panel vendors. It will be a while before we see Android tablets with comparable resolutions, although we will see 1920 x 1200 Android tablets shipping in this half.

The CPU & More
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  • tipoo - Saturday, March 10, 2012 - link

    Maybe I'm more sensitive to it but I can definitely see the pixels in the borders of things like the Safari icon. The AT images are zoomed in of course so you notice it more, but its pretty easy to see at a glance on the iPad 1 and 2. Reply
  • ananduser - Friday, March 09, 2012 - link

    What you didn't mention in your analysis is that the "new" resolution is the result of a need and not a wish to trump competition on specs. Apple couldn't have chosen 1600x1200 or 1920x1200 or standard 1080p because of ios' lack of resolution independence. As they did with the iphone, Apple invested in a custom screen size just so that the ecosystem would introduce a x2 and voila, instant upgrade. Reply
  • ZeDestructor - Friday, March 09, 2012 - link

    Not really custom. High-end 19"+ CRTs back in the late 90s did 2048x1536@72+Hz as a matter of routine. Reply
  • Roland00Address - Friday, March 09, 2012 - link

    Nobody is shipping a device with a 1600x1200 or 1920x1200. Yes there will be competitors later on this year with those resolutions but no body is shipping an ips panel with those resolutions in a 10 inch form factor right now. Thus Apple is not saving money by merely retooling some other panel.

    Yet there is a reason besides higher dots per inch for choosing something with greater than 1200 height. When you turn the tablet so the skinner side is going from left to right that means the maximum webpage it can draw is 1200 pixels wide without zooming or not showing the entire website. Most webpages are designed for the following resolutions. 1024x768, 1280x1024, 1366x768. By picking something that is at least 1366 wide you are guaranteed to display the entire webpage.

    Furthermore merely doubling the resolution makes it a lot easier to port apps to the higher screen resolution.

    If you need to get custom panels anyway why not pick a resolution that makes sense from an app development perspective as well as being more useful at displaying webpages. Why do you need to follow the resolutions that are traditional on desktops, an ipad is not a desktop device so why situate it with desktop baggage when you are starting from scratch?
    Reply
  • joelypolly - Saturday, March 10, 2012 - link

    It isn't a new resolution and has been a standard LCD resolution call QXGA for many years. In fact IBM shipped a 15" Thinkpad with QXGA screens which looked awesome compared to the standard XGA screens at the time. Reply
  • doobydoo - Monday, March 12, 2012 - link

    It's not because of a 'lack of resolution independence' at all. The iPhone and iPad both have different pixel ratios and both run iOS.

    It's to make life easier for app developers, and means that any existing apps for the iPad 1 or 2 can be scaled up automatically.

    The Samsung Galaxy got this wrong by switching the ratio between generations. It quickly gets very messy for developers.
    Reply
  • prophet001 - Friday, March 09, 2012 - link

    Hey Anand,
    I was wondering if you could elaborate more on the differences between the usability of a tablet and that of a laptop. Perhaps write a short article. I know that there are substantial hardware differences. However, what are the OS level differences that restrict what things you can do on a tablet? Thanks for this article and all you guys do.
    Reply
  • classy - Friday, March 09, 2012 - link

    It looks like a true top notch tablet, but the price just seems to high. I have found more often than not, unless you are a reader, a laptop is better. Reply
  • jihe - Friday, March 09, 2012 - link

    And if you are a serious reader, kindle is better Reply
  • SixOfSeven - Friday, March 09, 2012 - link

    Depends on what you're a serious reader of. If it's technical literature, you need size and resolution. If it's a novel, pretty much anything will do (hence the Kindle). The first two iPads require too much panning and zooming for the sort of stuff I read; perhaps this one will be better. Reply

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