The iPhone 5 Review
by Anand Lal Shimpi, Brian Klug & Vivek Gowri on October 16, 2012 11:33 AM EST- Posted in
- Smartphones
- Apple
- Mobile
- iPhone 5
GPU Analysis/Performance
Section by Anand Shimpi
Understanding the A6's GPU architecture is a walk in the park compared to what we had to do to get a high level understanding of Swift. The die photos give us a clear indication of the number of GPU cores and the width of the memory interface, while the performance and timing of release fill in the rest of the blanks. Apple has not abandoned driving GPU performance on its smartphones and increased the GPU compute horsepower by 2x. Rather than double up GPU core count, Apple adds a third PowerVR SGX 543 core and runs the three at a higher frequency than in the A5. The result is roughly the same graphics horsepower as the four-core PowerVR SGX 543MP4 in Apple's A5X, but with a smaller die footprint.
As a recap, Imagination Technologies' PowerVR SGX543 GPU core features four USSE2 pipes. Each pipe has a 4-way vector ALU that can crank out 4 multiply-adds per clock, which works out to be 16 MADs per clock or 32 FLOPS. Imagination lets the customer stick multiple 543 cores together, which scales compute performance linearly.
SoC die size however dictates memory interface width, and it's clear that the A6 is significantly smaller in that department than the A5X, which is where we see the only tradeoff in GPU performance: the A6 maintains a 64-bit LPDDR2 interface compared to the 128-bit LPDDR2 interface in the A5X. The tradeoff makes sense given that the A5X has to drive 4.3x the number of pixels that the A6 has to drive in the iPhone 5. At high resolutions, GPU performance quickly becomes memory bandwidth bound. Fortunately for iPhone 5 users, the A6's 64-bit LPDDR2 interface is a good match for the comparatively low 1136 x 640 display resolution. The end result is 3D performance that looks a lot like the new iPad, but in a phone:
| Mobile SoC GPU Comparison | |||||||||||
| Adreno 225 | PowerVR SGX 540 | PowerVR SGX 543MP2 | PowerVR SGX 543MP3 | PowerVR SGX 543MP4 | Mali-400 MP4 | Tegra 3 | |||||
| SIMD Name | - | USSE | USSE2 | USSE2 | USSE2 | Core | Core | ||||
| # of SIMDs | 8 | 4 | 8 | 12 | 16 | 4 + 1 | 12 | ||||
| MADs per SIMD | 4 | 2 | 4 | 4 | 4 | 4 / 2 | 1 | ||||
| Total MADs | 32 | 8 | 32 | 48 | 64 | 18 | 12 | ||||
| GFLOPS @ 200MHz | 12.8 GFLOPS | 3.2 GFLOPS | 12.8 GFLOPS | 19.2 GFLOPS | 25.6 GFLOPS | 7.2 GFLOPS | 4.8 GFLOPS | ||||
We ran through the full GLBenchmark 2.5 suite to get a good idea of GPU performance. The results below are largely unchanged from our iPhone 5 Performance Preview, with the addition of the Motorola RAZR i and RAZR M. I also re-ran the iPad results on iOS 6, although I didn't see major changes there.
We'll start out with the raw theoretical numbers beginning with fill rate:
The iPhone 5 nips at the heels of the 3rd generation iPad here, at 1.65GTexels/s. The performance advantage over the iPhone 4S is more than double, and even the Galaxy S 3 can't come close.
Triangle throughput is similarly strong:
Take resolution into account and the iPhone 5 is actually faster than the new iPad, but normalize for resolution using GLBenchmark's offscreen mode and the A5X and A6 look identical:
The fragment lit texture test does very well on the iPhone 5, once again when you take into account the much lower resolution of the 5's display performance is significantly better than on the iPad:
The next set of results are the gameplay simulation tests, which attempt to give you an idea of what game performance based on Kishonti's engine would look like. These tests tend to be compute monsters, so they'll make a great stress test for the iPhone 5's new GPU:
Egypt HD was the great equalizer when we first met it, but the iPhone 5 does very well here. The biggest surprise however is just how well the Qualcomm Snapdragon S4 Pro with Adreno 320 GPU does by comparison. LG's Optimus G, a device Brian flew to Seoul, South Korea to benchmark, is hot on the heels of the new iPhone.
When we run everything at 1080p the iPhone 5 looks a lot like the new iPad, and is about 2x the performance of the Galaxy S 3. Here, LG's Optimus G actually outperforms the iPhone 5! It looks like Qualcomm's Adreno 320 is quite competent in a phone. Note just how bad Intel's Atom Z2460 is, the PowerVR SGX 540 is simply unacceptable for a modern high-end SoC. I hope Intel's slow warming up to integrating fast GPUs on die doesn't plague its mobile SoC lineup for much longer.
The Egypt classic tests are much lighter workloads and are likely a good indication of the type of performance you can expect from many games today available on the app store. At its native resolution, the iPhone 5 has no problems hitting the 60 fps vsync limit.
Remove vsync, render at 1080p and you see what the GPUs can really do. Here the iPhone 5 pulls ahead of the Adreno 320 based LG Optimus G and even slightly ahead of the new iPad.
Once again, looking at GLBenchmark's on-screen and offscreen Egypt tests we can get a good idea of how the iPhone 5 measures up to Apple's claims of 2x the GPU performance of the iPhone 4S:
Removing the clearly vsync limited result from the on-screen Egypt Classic test, the iPhone 5 performs about 2.26x the speed of the 4S. If we include that result in the average you're still looking at a 1.95x average. As we've seen in the past, these gains don't typically translate into dramatically higher frame rates in games, but games with better visual quality instead.
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Sufo - Tuesday, October 16, 2012 - link
Agreed. If his goal is to fly the flag for apple (who clearly need no flag flying - look at their stock prices, but i digress...), and discredit its detractors, he's doing an awful job. But then again, I do detect a whiff of troll.Spunjji - Friday, October 19, 2012 - link
Word.doobydoo - Saturday, October 20, 2012 - link
Bragging? About being an engineer?LOL
dagamer34 - Tuesday, October 16, 2012 - link
If you wanted a "should I upgrade to this phone" review, there are hundreds of those reviews online. But AnandTech is pretty much the only place where you get a definitive review worth reading 5 years from now. They leave no stone unturned.Arbee - Tuesday, October 16, 2012 - link
Agreed. "Should I upgrade" is covered by literally dozens of newspapers, TV shows, and websites (Engadget, The Verge, Gizmodo, All Things D just to name 4). AT is the home of the 15+ page deep dive, and they do it just as well for Androids and Windows Phones.Also, I'm completely positive that if you sent Brian a GS3 with the iPhone 5's camera he'd write about it in exactly the same way. 2 weeks ago DPReview covered the iPhone 5's camera in a very similar way (including the same suggestions on how to avoid the problem, and a demonstration of inducing similar artifacts on the iPhone 4S and a couple of Android handsets). Optics is not a soft science, there is no room for fanboyism.
rarson - Wednesday, October 17, 2012 - link
I totally disagree. He brings up a completely valid point because Anandtech usually separates the reviews from the in-depth tech examinations. There's absolutely no need for the review to be 20 pages when most people are looking for benchmarks and hands-on impressions. Considering the fact that going this in-depth made the review late, it makes no sense at all.At least half of this information in this article doesn't even fall under the category of a review.
darkcrayon - Tuesday, October 16, 2012 - link
I think this type of review (hell, the site in general) is directed at people that want the maximum amount of compiled nitty gritty techy details... Notice his review was weeks after the larger more general consumer oriented sites. I think anyone wanting to know whether they should upgrade, that isn't interested in the technical details of the A6, would be better served reading those reviews anyway.Anand has said in previous reviews that he felt that iOS was intended to be more of an "appliance" OS. It's a pretty apt comparison of the two actually. That focus is why you can side load and more easily put custom software on Android, and also why you'll need anti-malware software for it before long as well. The point of an appliance is to have a reliable, consistent device that you spend more time using than tweaking.
daar - Wednesday, October 17, 2012 - link
Point taken, darkcrayon.I prefer AT's reviews because they do a thorough and unbiased job at detailing/benchmarking and comparing different products. The suggestion was that the info about the SoC be split on it's own. If Intel released a new chip, call it i9, and the first sample was from an Alienware notebook, I would simply be suggesting that the technical info about the chip have it's own post and not be combined with the review of the notebook is all.
I find it a bit strange that people are suggesting to go to other websites when I made the comment of comparisons to other products, and quite unlike most posts in AT reviews. If I make a comment about a few ATI features not being compared with Nvidia's, I would have been surprised to have people to tell me to go visit Tom's Hardware or the like.
Not to say there wasn't any comparisons, but rather in contrast to say, for example, the One X review where Brian made the comment of how the construction of the device felt better than the GS3. It felt like punches were being pulled in this review is all.
phillyry - Sunday, October 21, 2012 - link
Anand,I would like to know, however, how an Android device serves more as an all purpose device than an iPhone.
Did you mean because of its customisable skins or because it can do some things that an iPhone cannot - presumably because of Apple's strong hold ('death grip') on the OS?
This is pretty important to me because I am near the end of the term of my agreement and am in the market for a new 'phone'. I've considered W8P for precisely this reason but am waiting to see if they flop or not. I've always thought of Android as pretty darn similar to iOS but with slightly different interfaces and less user restrictions.
Is there some other factor that makes an Android any more like a pocket computer, like the future x86 W8P phones will presumably eventually be, and less like an iPhone than I have imagined?
phillyry - Sunday, October 21, 2012 - link
I also took notice of it when Anand referred to the iPhone as an appliance. Your remark saying, "The point of an appliance is to have a reliable, consistent device that you spend more time using than tweaking" would be comforting but I don't think that that's quite how Anand meant it. I was actually quite put off by the term because I think that he meant that the iPhone is made to be more of a tag along device that goes with your other Macs and plays a support role rather than a stand alone device. He pretty much says as much.Like I said, I found this a bit off putting but I think he's just saying how he sees it in terms of the respective companies' product lines and agendas. It actually makes a fair bit of sense. I found that when I got an iPhone it made me want an iPad. And then when I got an iPad it made me want a MacBook. Call it what you will but I remember thinking that they should be able to make it so that I can do everything I need to on an iPad but distinctly felt like I really needed a MacBook to really do all that I wanted. It could be argued, along the lines of Anand's original comment, that this is Apple's approach / business model.
It also points to a distinction between Apple and the other big player that no one in this forum is talking about - Microsoft. Windows 8 appears to be meant to be the exact opposite of this approach. Instead of one device for each purpose it's one device for all purposes. It will be interesting to see if Microsoft's approach with Windows 8 will turn things around or simply flop, at least on the handheld device side of things.