4 ms·

The benchmarks of the processor performance show that it's twice as fast as the A5. About 1/4 of that can be attributed to the clock frequency. There's really

The benchmarks of the processor performance show that it's twice as fast as the A5. About 1/4 of that can be attributed to the clock frequency. There's really nothing left but the IPC to attribute the remaining (~75%) gain in performance.

ajross 14y ago
Cite? I know Apple's marketing says it's twice as fast, but (even skipping the fact that it's marketting spin) that can be terribly polluted by things like the fact that the DRAM bus is twice as wide. That can be a huge gain in some circumstances, but has absolutely nothing to do with transistor count in the rest of the die. I was hoping for something like a cache-bound CPU test that can look at IPC specifically.
- m_eiman 14y ago
  Anandtech did some benchmarks a few days ago: http://www.anandtech.com/show/6309/iphone-5a6-sunspider-performance http://www.anandtech.com/show/6309/iphone-5a6-sunspider-perf...
  - sureshv 14y ago
    Sunspider is not an IPC type benchmark, you have to run the same app on both processors. I would assume the browser has changed substantially since the last update. Perhaps they have improved the JIT as well.
    - m_eiman 14y ago
      There are also a number of other tests in the article, this page just happened to be the first hit when I searched for it. Overall improvements are around 2x.
  - ralfd 14y ago
    Just updated my 4S and run Sunspider before (2150) and after (1864). So a bit of the improvement is iOS 6 and not the new hardware alone.
mtgx 14y ago
It's not 1/4. More like 50% of the increase in performance. The A6 CPU is 1.2 Ghz compared to the 800 Mhz CPU in iPhone 4S (both dual core). And as others have mentioned, you can't really base that on Sunspider alone. Sunspider is not a hardware-only benchmark. You need the DMIPS number, which is what ARM is using for its own chips, too. So if the increase from clock speed alone is 50%, that means a 1.5x multiplier, which means the "other" IPC multiplier is somewhere between 1.3x-1.4x (to get 2x over iPhone 4S), which would be on par with Krait and Cortex A15. Also, when comparing processors running Android vs processors running iOS, it's also important to take note not only of the difference in OS, but also in browsers (related to the browser tests I've seen so far).
- codex 14y ago
  Are the power draws from the A6, Krait and Cortex A15 presumed to be equal? Would it be possible to reduce performance in return for lower power at a constant clock speed? If so, it seems that one cannot talk about IPC without also knowing the power draw.
- ajross 14y ago
  You're forgetting the ~15% improvement from pure software in the iOS 6 Javascript interpreter mentioned elsewhere. Combining those, I get 2/((2150/1864)*(1200/800))== 1.156. So a 16% improvement in IPC. That's much more in line with what we see elsewhere in the industry for this sort of increase in transistor count (c.f. Nehalem to Sandy Bridge, etc...)

ajross 14y ago

Cite? I know Apple's marketing says it's twice as fast, but (even skipping the fact that it's marketting spin) that can be terribly polluted by things like the fact that the DRAM bus is twice as wide. That can be a huge gain in some circumstances, but has absolutely nothing to do with transistor count in the rest of the die. I was hoping for something like a cache-bound CPU test that can look at IPC specifically.

m_eiman 14y ago
Anandtech did some benchmarks a few days ago: http://www.anandtech.com/show/6309/iphone-5a6-sunspider-performance http://www.anandtech.com/show/6309/iphone-5a6-sunspider-perf...
- sureshv 14y ago
  Sunspider is not an IPC type benchmark, you have to run the same app on both processors. I would assume the browser has changed substantially since the last update. Perhaps they have improved the JIT as well.
  - m_eiman 14y ago
    There are also a number of other tests in the article, this page just happened to be the first hit when I searched for it. Overall improvements are around 2x.
- ralfd 14y ago
  Just updated my 4S and run Sunspider before (2150) and after (1864). So a bit of the improvement is iOS 6 and not the new hardware alone.

mtgx 14y ago

It's not 1/4. More like 50% of the increase in performance. The A6 CPU is 1.2 Ghz compared to the 800 Mhz CPU in iPhone 4S (both dual core). And as others have mentioned, you can't really base that on Sunspider alone. Sunspider is not a hardware-only benchmark. You need the DMIPS number, which is what ARM is using for its own chips, too. So if the increase from clock speed alone is 50%, that means a 1.5x multiplier, which means the "other" IPC multiplier is somewhere between 1.3x-1.4x (to get 2x over iPhone 4S), which would be on par with Krait and Cortex A15. Also, when comparing processors running Android vs processors running iOS, it's also important to take note not only of the difference in OS, but also in browsers (related to the browser tests I've seen so far).

codex 14y ago
Are the power draws from the A6, Krait and Cortex A15 presumed to be equal? Would it be possible to reduce performance in return for lower power at a constant clock speed? If so, it seems that one cannot talk about IPC without also knowing the power draw.
ajross 14y ago
You're forgetting the ~15% improvement from pure software in the iOS 6 Javascript interpreter mentioned elsewhere. Combining those, I get 2/((2150/1864)*(1200/800))== 1.156. So a 16% improvement in IPC. That's much more in line with what we see elsewhere in the industry for this sort of increase in transistor count (c.f. Nehalem to Sandy Bridge, etc...)