The A6 GPU: PowerVR SGX 543MP3?

Apple made a similar "up to 2x" claim for GPU performance. It didn't share any benchmarks, but there are four options here:

1) PowerVR SGX 543MP2 (same as in A5) at 2x the clock speed
 
2) PowerVR SGX 543MP4 at the same clock as the MP2 in the A5
 
3) Marginally higher clocked PowerVR SGX 543MP3
 
4) Next-gen PowerVR Rogue GPU
 
It's too early for #4. The first option makes sense but you run into the same issues as on the CPU side with higher voltages used to ramp clocks up (also possible that you drop voltages in the move to the new process technology). 
 
The second option trades voltage for die area, which based on the A5X Apple is clearly willing to spend where necessary.
 
The third is sort of the best of both worlds. You don't take a huge die area penalty and at the same time don't run at a significantly higher frequency, and you can get to that same 2x value.

The third option is the most elegant and likely what Apple chose here. Remember that overall die size is dictated by the amount of IO you have around the chip. The A5X had four 32-bit LPDDR2 memory controllers, which gave Apple a huge die area to work with. The move to a smaller manufacturing process cuts down the total die area, which means Apple would either have to add a ton of compute (to fill empty space, no sense in shipping a big chip with a bunch of unused area) or reduce the memory interface to compensate. Pair that knowledge with the fact that Apple doesn't have the same memory bandwidth requirements on the iPhone 5 (0.7MP vs. 3.1MP display) and it makes sense that Apple would go for a narrower memory interface with the A6 compared to the A5X.
 
How much narrower? Phil Schiller mentioned the A6 was 22% smaller than the A5. We can assume this is compared to the 45nm A5 and not the 32nm A5r2, which would mean that we don't have any more memory channels compared to the A5. In other words, it's quite likely the A6 has a 2x32-bit LPDDR2 memory interface once again.
 

Final Words

 
There's not much more to add for now. We'll have a device in a week and I suspect the first reviews will be out a day or two before then. Then the real work begins on finding out exactly what Apple has done inside the A6. If anyone has been dying to put together some good low level iOS benchmarks, now is the time to start.
 
This is a huge deal for Apple. It puts the company in another league when it comes to vertical integration. The risks are higher (ARM's own designs are tested and proven across tons of different devices/platforms) but the payoff is potentially much greater. As Qualcomm discovered, it's far easier to differentiate (and dominate?) if you're shipping IP that's truly unique from what everyone else has.
 
Now we get to see just how good Apple's CPU team really is.
The A6's CPU
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  • techconc - Monday, September 17, 2012 - link

    @tobi1449:

    Certainly, you've never actually used an iPhone 4 otherwise you'd know that your claims are patently false. My wife has an iPhone 4, you can't just make the signal completely drop by bridging the antenna gap. This "issue" didn't result in any more actual lost calls than other phones. The "issue" was corrected in software as to how the signal strength was being reported. Yes, multi-antenna designs are more consistent with regard to reception but even at it's worst, the iPhone 4 design is nowhere near what you describe. Further, this discussion is a bit off topic.
    Reply
  • rarson - Tuesday, September 18, 2012 - link

    Yeah, and that class action lawsuit for Mag"Safe" adapters catching fire didn't happen either.

    Apple products suck. They really do.
    Reply
  • moogleii - Tuesday, September 18, 2012 - link

    Your response to his antenna argument is a giant red herring? I guess all car manufacturers suck because at some point in time, one of their products had an issue. Or any manufacturer really.

    http://www.arcfn.com/2012/05/apple-iphone-charger-...

    Looks like quality engineering there to me. But hey, let's all resort to knee-jerk fanboy-ism.

    Your argument sucks. It really does. Honestly, I shouldn't even have bothered.
    Reply
  • moogleii - Tuesday, September 18, 2012 - link

    I don't think it's as certain as you think it is. There are tests showing it happening on different designs as well (in fact, there's one on this site).

    http://www.anandtech.com/show/3821/iphone-4-redux-...

    It did not drop to zero. It attenuated the signal. If you had abysmal signal, sure, it could/would drop. If you had high signal, certainly not. From anandtech's own tests, worst case, a 24 dB drop in signal.

    It's not clearcut issue. By their own tests, in some situations the antenna improved things, and in some cases, it didn't.
    Reply
  • tuxRoller - Sunday, September 16, 2012 - link

    This is what I've wondered, especially with the MSM8960T soon to be available.
    I guess we'll see since I didn't notice any references in this article other than "unpublishable" info about it not being cortex a9 based.
    Reply
  • Death666Angel - Saturday, September 15, 2012 - link

    Probably, but I don't think it was wrong to doubt their abilities up to this point. A4/A5 wasn't exactly brilliant in any novel way. :-)

    Good read, thanks for that!

    Can someone explain ARM naming to me? They have Cortex A8, A9, A15 which get faster in the order of their numbers. Then they have Cortex A5 which is for new low end SoCs. Where are Cortex A10-A14? Are they in other markets? NAS or routers or something? Wouldn't mind some enlightenment. :D
    Reply
  • Exophase - Saturday, September 15, 2012 - link

    They're not version numbers that increase by one with regard to anything, so no there aren't other versions with the missing numbers, although you did miss Cortex-A7.

    I think that the number is meant to give some rough indicator of relative performance. A9 was released after A8 and is somewhat faster. A7 is marginally slower than A8. A5 is slower than A8 and A9, but not half the speed as either. A15 is substantially faster than A9. Of course it's not all linear with respect to benchmarks or anything but it gives you a good feel.

    ARM does have two other product profiles (M and R) and I think the numbering there at least kind of fits in with this scheme, in that Cortex-M0/M1/M3/M4 and Cortex-R4/R5 all scale in performance in that order, and note that all the Cortex-M series are given numbers below 5 as they're all slower than Cortex-A5, but Cortex-R5 is on a similar performance level so doesn't have that restriction. The relation in numbering between different profiles is even cruder, but probably does still give a rough boundary point.
    Reply
  • dagamer34 - Saturday, September 15, 2012 - link

    I think A7 is almost meant to mimic the performance of Cortex A8 at a much smaller power envelope to complement A15 in a big.LITTLE arrangement in high end smartphones/tablets in the coming years or in a dual A7 arrangement for low to midrange CPUs. Reply
  • ratte - Saturday, September 15, 2012 - link

    Nice update on the A6.
    Will be really interesting to see the testresults
    Reply
  • zanon - Saturday, September 15, 2012 - link

    Thanks for the write up Anand, this is an interesting step forward and I very much look forward to seeing what they've put together. We've known for years that Apple has been acquiring significant chip design talent (P. A. Semi being a major example), but I think this will be the first time we'll get to see it really put to use at the lowest and most core levels, rather then merely SoC integration or peripheral stuff.

    It's been many years since we last saw a wide array of companies trying to make different CPUs. It'll be very interesting to see what all comes of it.
    Reply

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