As always, our good friends over at Kishonti managed to have the first GPU performance results for the new 4th generation iPad. Although the new iPad retains its 2048 x 1536 "retina" display, Apple claims a 2x improvement in GPU performance through the A6X SoC. The previous generation chip, the A5X, had two ARM Cortex A9 cores running at 1GHz paired with four PowerVR SGX 543 cores running at 250MHz. The entire SoC integrated 4 x 32-bit LPDDR2 memory controllers, giving the A5X the widest memory interface on a shipping mobile SoC in the market at the time of launch.

The A6X retains the 128-bit wide memory interface of the A5X (and it keeps the memory controller interface adjacent to the GPU cores and not the CPU cores as is the case in the A5/A6). It also integrates two of Apple's new Swift cores running at up to 1.4GHz (a slight increase from the 1.3GHz cores in the iPhone 5's A6). The big news today is what happens on the GPU side. A quick look at the GLBenchmark results for the new iPad 4 tells us all we need to know. The A6X moves to a newer GPU core: the PowerVR SGX 554.

Mobile SoC GPU Comparison
  PowerVR SGX 543 PowerVR SGX 543MP2 PowerVR SGX 543MP3 PowerVR SGX 543MP4 PowerVR SGX 554 PowerVR SGX 554MP2 PowerVR SGX 554MP4
Used In - iPad 2 iPhone 5 iPad 3 - - iPad 4
# of SIMDs 4 8 12 16 8 16 32
MADs per SIMD 4 4 4 4 4 4 4
Total MADs 16 32 48 64 32 64 128

As always, Imagination doesn't provide a ton of public information about the 554 but based on what I've seen internally it looks like the main difference between it and the 543 is a doubling of the ALU count per core (8 Vec4 ALUs per core vs. 4 Vec4). Chipworks' analysis of the GPU cores helps support this: "Each GPU core is sub-divided into 9 sub-cores (2 sets of 4 identical sub-cores plus a central core)."

I believe what we're looking at is the 8 Vec4 SIMDs (each one capable of executing 8+1 FLOPS). The 9th "core" is just the rest of the GPU including tiler front end and render backends. Based on the die shot and Apple's performance claims it looks like there are four PowerVR SGX554 cores on-die, resulting in peak theoretical performance greater than 77 GFLOPS.

There's no increase in TMU or ROP count per core, the main change between the 554 and 543 is the addition of more ALUs. There are some more low level tweaks which helps explain the different core layout from previous designs, but nothing major.

With that out of the way, let's get to the early performance results. We'll start with low level fill rate and triangle throughput numbers:

GLBenchmark 2.5 - Fill Test

Fill rate goes up by around 15% compared to the iPad, which isn't enough to indicate a huge increase in the number of texture units on the 554MP4 vs. the 543MP4. What we may be seeing here instead are benefits from higher clocked GPU cores rather than more texture units. If this is indeed the case it would indicate that the 554MP4 changes the texture to ALU ratio from what it was in the PowerVR SGX 543 (Update: this is confirmed). The data here points to a GPU clock at least 15% higher than the ~250MHz in the 3rd generation iPad.

GLBenchmark 2.5 - Fill Test (Offscreen 1080p)

GLBenchmark 2.5 - Triangle Texture Test

Triangle throughput goes up by a hefty 65%, these are huge gains over the previous generation iPad.

GLBenchmark 2.5 - Triangle Texture Test (Offscreen 1080p)

GLBenchmark 2.5 - Triangle Texture Test - Fragment Lit

The fragment lit triangle test starts showing us close to a doubling of performance at the iPad's native resolution.

GLBenchmark 2.5 - Triangle Texture Test - Fragment Lit (Offscreen 1080p)

GLBenchmark 2.5 - Triangle Texture Test - Vertex Lit

GLBenchmark 2.5 - Triangle Texture Test - Vertex Lit (Offscreen 1080p)

GLBenchmark 2.5 - Egypt HD

Throw in a more ALU heavy workload and we really start to see the advantage of the new GPU: almost double the performance in Egypt HD at 2048 x 1536. We also get performance that's well above 30 fps here on the iPad at native resolution for the first time.

GLBenchmark 2.5 - Egypt HD (Offscreen 1080p)

Normalize to the same resolution and we see that the new PowerVR graphics setup is 57% faster than even ARM's Mali-T604 in the Nexus 10. Once again we're seeing just about 2x the performance of the previous generation iPad.

GLBenchmark 2.5 - Egypt Classic

Vsync bound gaming performance obviously won't improve, but the offscreen classic test gives us an idea of how well the new SoC can handle lighter workloads:

GLBenchmark 2.5 - Egypt Classic (Offscreen 1080p)

For less compute bound workloads the new iPad still boasts a 53% performance boost over the previous generation.

Ultimately it looks like the A6X is the SoC that the iPad needed to really deliver good gaming performance at its native resolution. I would not be surprised to see more game developers default to 2048 x 1536 on the new iPad rather than picking a lower resolution and enabling anti-aliasing. The bar has been set for this generation and we've seen what ARM's latest GPU can do, now the question is whether or not NVIDIA will finally be able to challenge Imagination Technologies when it releases Wayne/Tegra 4 next year.

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  • Alucard291 - Friday, November 2, 2012 - link

    But they get soooo much hype its almost silly :)
  • CBone - Saturday, November 3, 2012 - link

    The problem with nvidia is that they obsolete their latest gpu by talking about the next one before anything even uses the current one.

    Does it get beaten in benches? Yes. Badly. But it's faster than crap in games and no one will do as much heavy lifting as nvidia to help optimize a game for their chips. I'll take that trade. Funny that the powervr designs are stomping through benches in apple stuff, but the same games on both platforms look better with tegra.
  • CeriseCogburn - Monday, November 5, 2012 - link

    I wondered what all the insane babbling idiots were talking about on 1st page of comments... LOL

    It sure is a lot of hot air when the real world GAMES and the like leave Jobs' PR monkeys sucking dirt and gagging on their words.

    I find it amazing how large the emotional hyper ditzy girl sensational self happy deception baggage is.

    Then half of them tell others they don't know what they're talking about....
    (roll eyes again, rinse and repeat, often)
  • steven75 - Monday, November 5, 2012 - link

    U jelly?
  • CeriseCogburn - Tuesday, November 6, 2012 - link

    Disappointed. We have another whole segment of babbling retards.
    Clueless idiots, the best we have in "tech" at the "most comprehensive and in depth" review site.

    Ashamed is the answer, ashamed that so many are so stupid and so estrogen doused that the feed of lies and fantasies is 10X longer than the simple and short facts.
  • mavere - Tuesday, November 6, 2012 - link

    "estrogen doused"

    Well then.
  • andsoitgoes - Saturday, November 10, 2012 - link

    Yeah. That was. Was. Probably the most interesting thing I've seen trolled on a site.

    I applaud the crazy. The crazy in that one is SSSSSTRONG.
  • djgandy - Monday, November 5, 2012 - link

    Yawn Nvidia fanboys even in the mobile market where they are a complete non player. Tegra's thermal characteristics are terrible. Nvidia always talks big, but they can't walk the walk.

    I find it hilarious that you think roadmaps can just be "outdated" and products magically moved forward. You clearly lack understanding of how complex hardware design and how long that cycle lasts. People are already sitting in rooms discussing requirements for what will be in your smartphone in 2017.
  • CeriseCogburn - Tuesday, November 6, 2012 - link

    Not sure what you're babbling about, but I did go look up the tegra 3, because I recalled reading here how the Appl competition at the time FAILED against it.

    Looks to me like you have a big chip on your shoulder... all sour about how you perceive nVidia to be talking...

    Another sad, biased, angry fanboy, with emotional issues.
  • djgandy - Thursday, November 8, 2012 - link

    Oh a video, lovely. What is it exactly we are looking at, a nice Nvidia Marketing demo of how their chip is better just like they have been doing for 10 years now?

    You didn't refute my point either. Look at T3 power consumption, the thing is only any use if its connected to the mains. Hardly meets the requirements for a mobile chip.

    Quad core CPU though, how useful, I've always wanted to do Folding@WhereverIAm over 3G.

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