GPU Performance

Since the iPad Air uses the same A7 silicon as the iPhone 5s, it also uses the same on-die GPU as the 5s: IMG’s PowerVR G6430. This is a 4-cluster configuration of IMG’s latest graphics hardware, running at some relatively high frequency. I already went into some detail on the G6430 in our 5s review so I won’t rehash that here, but we’re basically looking at a shift to a more efficient scalar architecture.

I still don’t have confirmations of clock speeds, but I believe we’re looking at a max GPU clock of around 450MHz. As you’ll see from the results below, there’s a small difference in performance between the iPad Air and iPhone 5s in terms of peak GPU performance - implying very similar clocks. The difference is the iPad Air should be able to sustain its max frequency longer than the iPhone 5s can.

Mobile SoC GPU Comparison
  PowerVR SGX 554MP4 PowerVR G6430 PowerVR G6430
Used In iPad 4 iPhone 5s iPad Air
SIMD Name USSE2 USC USC
# of SIMDs 32 4 4
MADs per SIMD 4 32 32
Total MADs 128 128 128
GFLOPS @ 300MHz 76.8 GFLOPS 76.8 GFLOPS 76.8 GFLOPS
GFLOPS as Shipping 68.1 GFLOPS (?) 115.2 GFLOPS 115.2 GFLOPS

Since we’re talking about an A7 here and not an X-series SoC, there’s still only a 64-bit wide memory interface. As memory bandwidth is a key enabler of GPU performance I was curious to see how GPU performance compared to the outgoing iPad 4 with its much wider memory interface. Do keep in mind that the A7 does include a large system cache on-die, which can help improve effective memory bandwidth.

GFXBench 2.7

We'll start our GPU performance analysis with a look at low level results using GFXBench/GLBenchmark 2.7. The low level tests, particularly the offscreen ones, should give us some idea as to whether or not there's any increase in GPU frequency for the iPad Air vs. iPhone 5s implementations of A7.

GLBenchmark 2.7 - Fill Test (Onscreen)

GLBenchmark 2.7 - Fill Test (Offscreen)

Looking at the fill rate results, there's a 4.5% increase in performance compared to the iPhone 5s. That could be the magnitude of clock increase that we're seeing between A7s. Apple could very well be relying on more thermal headroom in the iPad Air to provide any real world GPU performance advantages over the iPhone 5s.

GLBenchmark 2.7 - Triangle Throughput (Onscreen)

GLBenchmark 2.7 - Triangle Throughput (Offscreen)

We see an even smaller gap between the Air and 5s in the triangle throughput tests (2.9%). There doesn't seem to be any substantial difference in GPU frequency between A7 implementations here. The regression in triangle rate performance compared to the iPad 4 is explained by differences in how Series 6 and Series 5XT GPUs scale in width. Whereas 5XT replicated nearly the entire GPU for "multi-core" versions, multi-cluster versions of Rogue only replicate at the shader array. The result? We don't see the same sort of peak triangle setup scaling we did back on multi-core 5XT parts. I'm not sure I'm particularly happy with the magnitude of the regression here, but I haven't seen any real world cases where it matters yet.

Next up are the game simulation tests. We'll start with the more strenuous of the two: T-Rex HD.

GLBenchmark 2.7 - T-Rex HD (Onscreen)

Here we get closer to Apple's claims of a 2x increase in performance. The iPad Air delivers 75% more performance than the iPad 4 in this test. Once again the iPhone 5s pulls ahead but that's because the onscreen tests render at display resolution, which is lower on the 5s.

GLBenchmark 2.7 - T-Rex HD (Offscreen)

Offscreen performance sees similar scaling: ~69% better performance compared to the iPad 4.

GLBenchmark 2.5 - Egypt HD (Onscreen)

GLBenchmark 2.5 - Egypt HD (Offscreen)

3DMark

We're once again running 3DMark's newest Unlimited mode which does its best to run independently of v-sync and at a standard resolution across all devices. I've also included 3DMark Extreme results below that feature a few more comparison points.

3DMark Unlimited - Ice Storm

The overall Ice Storm scores show a 36% improvement in performance over the iPad 4 and an 8% increase compared to the iPhone 5s. Given the CPU frequency advantage of the A7 in the Air vs. the iPhone 5s, I'm guessing that's why we're seeing the performance gap we are here.

3DMark Unlimited - Graphics Score

If we focus exclusively on the GPU tests (which themselves are still CPU bound), the iPad Air's performance advantage over the iPad 4 grows to over 60%.

3DMark Unlimited - Graphics Test 1

3DMark Unlimited - Graphics Test 2

3DMark Unlimited - Physics Score

I'm still not entirely sure what's going on with the 3DMark Physics test, but we've seen this two reviews in a row now where Cyclone showed no performance increase at all compared to Swift despite this being largely a CPU test.

3DMark - Ice Storm (Extreme)

3DMark - Graphics Score (Extreme)

3DMark - Graphics Test 1 (Extreme)

3DMark - Graphics Test 2 (Extreme)

3DMark - Physics Score (Extreme)

Basemark X

Basemark X is a new addition to our mobile GPU benchmark suite. There are no low level tests here, just some game simulation tests run at both onscreen (device resolution) and offscreen (1080p, no vsync) settings. The scene complexity is far closer to GLBenchmark 2.7 than the new 3DMark Ice Storm benchmark, so frame rates are pretty low.

I'm still having random issues with Basemark X reliably running both on and offscreen tests on iOS 7. Unfortunately I could only get onscreen results for the iPad Air, which came in at 46% faster than the iPad 4. Note the iPad mini and iPhone 5s benefit from having lower native resolutions here, which is why they perform so well.

Basemark X (Onscreen)

CPU Changes, Performance & Power Consumption Display
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  • jelloboy - Saturday, November 2, 2013 - link

    I've been coming here for many years. Their breakdown of products are fantastic, I always checkout what they have to say about something before picking it up.
  • beggerking@yahoo.com - Saturday, November 2, 2013 - link

    Where is the nexus 5 review? Why is it not up yet?
  • golem - Sunday, November 3, 2013 - link

    Why are you expecting one so soon? Most major outlets only have previews or first impressions and Anandtech's reviews usually come late anyway.
  • jelloboy - Saturday, November 2, 2013 - link

    I just got my Air today, I'm upgrading from an iPad 3 and it's actually quite impressive in your hand, much more so than I thought it would be. Very comfortable and light to hold but still feels like an Apple product (which is a good thing) - very fast and the biggest thing I was worried about isn't an issue. I was worried since they cut some width off the sides that you might run into an issue of not having anyplace to rest your thumbs - however this isn't an issue at all. Since the iPad Air is a good amount lighter you don't to use as much leverage - plus I guess the software has some sort of thumb reject stuff in it - regardless it works.

    Obviously the unit is much faster than the iPad 3 - just generally usage is much more enjoyable on the Air. The iPad 3 wasn't slow, but it certainly wasn't as fast as my iPhone 5 - the Air obviously doesn't have the issue.

    So I wasn't sure if this new iPad would really be all that different, if the size and weight changes would be as dramatic as what I've read about here and other places - but I'm happy to say it really is quite an improvement.

    Also Android fanboys before you start crying, so you know I have 4 Sony Google TVs (which I love), and Nvidia Shield (which is awesome) and I've owned 3 different Android tablets over the years (Transformer TF100, Nexus 7, Transformer TF300). For the record the Android tablets are awful, terrible - slow, crappy software, lots of bugs. Meanwhile the Shield, which thinks it's a phone, actually runs very well. Anyways my point is Android has a long long long long long long way to go to be competitive in the tablet market. A long way.
  • Gadgetmanjohn - Sunday, November 3, 2013 - link

    I'm an Apple fan, I have an iPad 1 and 3 but skipped 4 as it came out too soon after I'd purchased the 3rd gen. However, having tried the iPad air in the shop I was completely put off by the sound vibrations through the chassis. You can feel it all the way from the bottom to the top, very off putting when watching video or playing music whilst holding it. I just can't believe more people aren't talking about it, let's hope the mini doesn't suffer the same problem.
  • Origin64 - Monday, November 4, 2013 - link

    You guys still pretending this is anything new? Same rectangle, different day.
  • Chrispy_ - Monday, November 4, 2013 - link

    No matter how good this device may be, I can't get over the fact that iOS7 is such a blatant copy for the visual style of Android. The default wallpaper on this reminds me of several of the 4.2 JellyBean wallpapers:

    http://www.smartkeitai.com/wp-content/uploads/2012...
    http://www.smartkeitai.com/wp-content/uploads/2012...
  • Brakken - Thursday, November 14, 2013 - link

    I was able to skin my android in iOS7 five months before iOS7 was released. Who's copying who now, huh? Huh?!
  • nasqb112 - Monday, November 4, 2013 - link

    Great review (as always) as this looks like an awesome device. I want to get an opinion from the Anandtech crowd:

    I currently have a MacBook Air (2011) and a Nexus 7 and want to consolidate.

    I was thinking Surface Pro 2 or iPad Air with keyboard case (similar to the Surface keyboard blades) as I need to be productive on the device. I'd also watch movies, surf the web, game while traveling, etc.

    Can anyone offer their thoughts on iWork vs Office (particularly for spreadsheets/data analysis and presentations?). I know what Office is supposedly coming to iPad, but I'll believe it when I see it.

    So what would you choose, Surface Pro 2 or iPad Air with keyboard and why? Thanks all!
  • tripleverbosity - Wednesday, November 13, 2013 - link

    If your biggest concern is running office I don't think the iPad Air with keyboard would be a good fit for you. Who knows when Office actually shows up for iOS and what level of functionality Microsoft will expose. As for iWork, it definitely isn't as comprehensive of an offering as Office at this point. That said, there's no way I'd buy a Surface Pro 2. If you can fit in into your budget, spend a couple hundred more and upgrade to the latest Macbook Air. It seems like you are trying to replace the laptop experience with a tablet/keyboard combo. Why not just go with a great laptop like the Air? You'll get better performance, better software capabilities, a superior keyboard and trackpad, and the best battery life out in the segment.

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