iPad 2

http://www.engadget.com/2011/03/09/ipad-2-review/
http://www.macworld.com/article/158439/2011/03/ipad2.html

Well Geekbench is reporting the iPad 2 has 512MB of RAM. And according to Macworld, the A5's system bus has doubled to 200MHz. Interestingly, Engadget said Geekbench is reporting the A5 at 800MHz. Double core Cortex A9 at 800MHz vs. single core Cortex A8 at 1GHz would be more consistent with Apple's 2x faster CPU claim. Although it does contradict the iPad 2 spec page which said the A5 is 1GHz. Perhaps the A5 is just downclocking or Geekbench needs to be updated.

 

Anand's take on iOS4.3 (first impressions): http://www.anandtech.com/show/4213/ios-43-review/1

 

Did you actually read the article I linked to, or did you just halt at the article title? The author makes an attempt to analyze Apple's current business model and he makes it perfectly clear that Apple's current business model has quite a few similarities to console manufacturers and NOT that the iPad or any other i-device is in the strict sense a "gaming console" of any sorts.

ltcommander just posted a link in the other thread from eeTimes: http://www.eetimes.com/electronics-news/4213873/Apple--TSMC-to-expand-foundry-ties

I'm still not sure if Apple's and analysts' forecasts are too optimistic or not. Time will tell eventually. However if those kind of volumes are true, it sounds like a reasonable assumption that prices will drop. Good news for the consumer and most likely bad news for Apple's competitors.

I haven't the vaguest idea what the GPU block is clocked at in A5, but assuming it's clocked somewhere in the 200MHz ballpark I don't see any absolute necessity to further increase the frequency for something like 720p. Apple considering to expand in that direction future AppleTV variants are at this time still just unverified rumors, yet it would be definitely interesting if they'd go in that direction. The major interest though in such a case would fall rather in the application store revenues direction than anything else.

 

Sounds like a worth while purchase for someone without an ipad that wants an ipad , certianly worth the premium over the current ipad 1 prices.

For those with an ipad it doesn't seem like its worth putting money out for

 

Overall faster performance is actually a godsend. Let's be honest, the original iPad is quite slow and I would pay money to get the faster performance and better user experience (less waiting around for websites to load and less caching issues with 512 MB of RAM).

Side-by-side comparisons will probably show a clearer picture, like loading a heavy website (e.g. Engadget or similar).

Also I am very excited about the increased graphics performance.

 

Geekbench

iPad2,3 - 743
http://browse.geekbench.ca/geekbench2/view/374870
Processor integer performance - 672
Processor floating point performance - 901
Memory performance - 808
Memory bandwidth performance - 317
Processor Frequency - 894 MHz
L2 Cache - 1.00 MB
Memory - 502 MB
FSB - 250 MHz

iPad1,1 - 449
http://browse.geekbench.ca/geekbench2/view/375950
Processor integer performance - 366
Processor floating point performance - 457
Memory performance - 645
Memory bandwidth performance - 320
Processor Frequency - 1.00 GHz
L2 Cache - 512 KB
Memory - 246 MB
FSB - 100.0 MHz

 

That's a very modest improvement - no wonder they've been able to keep the base model at 499 (euro).

Does this test use multiple cores properly? Or is this basically just comparing a single core?

 

??

Given the clock speeds it seems to scale about right...or am I missing something?

 

I could have just clicked the link. It's multi-threaded alright, and if I'm looking correct then from the looks of things single threaded performance is lower than the original iPad, right?

 

But it should be as the clock of the iPad2 is 10% lower.

 

Yeah, but that's not the point - you see on PCs that single-threaded applications on PC run slower on multi-core processors with lower clocks or core performance too. So it would be interesting to know what the typical behaviour is of applications on the iPad 2 vs the original iPad and see what circumstances give actual performance improvements, and/or if there are circumstances where the iPad 2 actually performs worse.

 

There is some strangeness with the Geekbench results.
The FSB difference 250MHz vs. 100MHz doesn't seem reflected in the memory scores at all, so I'd assume that either or both has issues.
Looking at the memory results, there are instances where the iPad2 is is twice as fast (stdlib write) and instances where it is slower (stdlib copy, even though read speeds are the same). Weird.

Looking at FP, in Mandelbrot (single threaded) the iPad2 is 3-4 faster, primality is over twice as fast and it seems clear that the FPU has changed substantially. Is A9 VFP pipelining enough to explain the difference?

Both run iOS 4.3 so library calls should be equivalent.

But again, the FSB and memory benchmark data look odd.
(Also, the actual bandwidth numbers should help explain why I'm always grumbling about SoC system wide limitations).

 

Maybe an Cortex-A8 without NEON extensions in the A4 and a dual A9 with NEON extensions (and VFP) in the A5 ?

 

Does the notion of FSB even make sense for SoC like A5?

 

Daring Fireball aka John Gruber did perhaps the most interesting review.

He asked a developer to code a program to quickly determine the performance of the 3D subsystem and the results are very nice:

 

John Gruber ran a custom benchmark:

http://daringfireball.net/2011/03/the_ipad_2

 

What are the details of the test? It could be you're just running into caching issues.

It depends on the particular instruction as well as load-use dependencies. A9 latencies (along with being pipelined) are less than half that of the A8 (FADD is 4 cycles vs 9 for SP). That can make a big difference. A9 also (IIRC) doesn't suffer the same penalties for subnormal numbers as the A8 does.

 

There is still a system bus (assuming they're like most other mobile SoC's) that connects the high-performance subsystems. That's usually fairly close if not synchronous to the memory speed. In a stock ARM system, I believe this bus also hosts the L2 cache as well.

 

The fact that two instances of a benchmark on the iPad 2 runs less than twice the speed of a single instance on the iPad just means that the iPad 2 is memory bottlenecked.

A 800MHz Cortex A9 would beat a 1GHz Cortex A8 hands down on real code (as in real iPad application code)

Cheers

 

A4 has NEON. You won't find a Cortex-A8 without NEON anyway, but I know for a fact A4 does - 3GS as well.

Look at more than just the very first benchmark. All the other integer numbers are decently to substantially higher, and this is with the iPad 2 allegedly at 900MHz vs 1GHz for the iPad. As indicated, the FPU results are a dead giveaway of it not being on a Cortex-A8.

Bus speed doesn't say anything about bus width: I'm pretty sure it's 64-bit in iPad, but could very well be 32-bit in iPad 2. nVidia seems to think 32-bit is enough for dual core Cortex-A9, afterall (or even quad-core)