TiPb Answers: Apple A5 chip -- what we know and what we guess

Apple A5 chip -- what we know and what we guess

Just like the original iPad debuted with an Apple A4 chip, iPad 2 is coming with an Apple A5 chip. What does that mean? In typical fashion Apple has been short on details saying only that it's dual-core, 1GHz, 2x faster for computational tasks and 9x faster for graphics, all while preserving the 10 hour battery life that made the A4 famous. They don't think we need to worry about what CPU or GPU they're using and how much RAM is on board to let that power breathe. But here's the thing -- many of us want to know exactly that.

This is the chip that will also power the 2011 iPhone 5, iPod touch 5, and Apple TV. We want answers. We can handle answers! So... stick with us after the break for everything we know about the new Apple A5 chip... and what we can guess.


Here's what Apple has to say about the new dual-core CPU:

Two powerful cores in one A5 chip mean iPad can do twice the work at once. You’ll notice the difference when you’re surfing the web, watching movies, making FaceTime video calls, gaming, and going from app to app to app. Multitasking is smoother, apps load faster, and everything just works better.

iPad, like all iOS devices is ARM-based. The original iPad used a single core Cortex A8 processor sped up to 1GHz, presumably by the geniuses at Intrisity -- a company Apple subsequently acquired. Apple is still a massive ARM licensee and the successor to the Cortex A8 is the multicore Cortex A9. This chip is forming the heart iPad competitors and it makes sense that Apple is using it in iPad 2 as well.

The Cortex A9 can scale upwards of 2GHz and while some may be disappointed Apple is sticking to 1GHz for iPad 2 there are always trade offs to be made, including temperature and most importantly -- battery life. If 2 times 1GHz cores are enough to give Apple the performance they want, the flexibility to do things like driving the iPad with one core and the HDMI-out display mirroring with the other, and keep 10 hours of battery life, that's a huge win.

UPDATE: It could also be dual ARM Cortex A8 cores


And here's Apple on their new graphics performance:

With up to nine times the graphics performance, gameplay on iPad is even smoother and more realistic. And faster graphics help apps perform better — especially those with video. You’ll see it when you’re scrolling through your photo library, editing video with iMovie, and viewing animations in Keynote.

Apple has been using Imagination's PowerVR GPU's in iOS and since they own a stake in the company that's also unlikely to change. The latest generation PowerVR SGX543 is a likely candidate here, perhaps dual core as well. Apple is not only pushing tons of pixels for video and gaming on-device, but offering up to 1080p out as well. 9x graphics performance is a big claim, but this chip with its OpenGL 3.2 support is big enough to match it.

It will also be interesting to see if Apple is using their own OpenCL in A5, which lets the GPU help out the CPU when it's not otherwise engaged.


Apple doesn't talk about RAM in iOS devices. Not ever. The original iPad had an anemic 256 MB of RAM. That wasn't even enough to keep a few Safari pages in memory. iPhone 4 has 512 MB and wild internet rumors aside, that's the minimum we should see in iPad 2.

Competing tablets are going to ship with 1GB of RAM and it would be great to see Apple match that but given the economics of hitting a $499 price point, they'll try to get the most performance they can out of the least hardware they can so I'm not getting my hopes up.

Battery life

Hey, it's still phenomenal:

Even with the new thinner and lighter design, iPad has the same amazing 10-hour battery life.1 That’s enough juice for one flight across the ocean, or one movie-watching all-nighter, or a week’s commute across town. The power-efficient A5 chip and iOS keep battery life from fading away, so you can get carried away.

And Apple's making it a huge priority, which again means balancing out multiple cores, cycles, and memory with power efficiency.

The tear-down will tell

Apple won't be talking about A5 in detail any time soon, so we'll have to wait for March 11 and the iPad 2 to ship before it gets torn down and we find out for sure. Until then, those are my best guesses. What are yours?

Have something to say about this story? Leave a comment! Need help with something else? Ask in our forums!

Rene Ritchie

EiC of iMore, EP of Mobile Nations, Apple analyst, co-host of Debug, Iterate, Vector, Review, and MacBreak Weekly podcasts. Cook, grappler, photon wrangler. Follow him on Twitter and Google+.

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Reader comments

TiPb Answers: Apple A5 chip -- what we know and what we guess


Remember guys 1 GHz dual-core != 2 GHz uni-core. When you go multi-core, CPU performance really becomes a system throughput metric. Everything won't be 2x as fast, just the embarrassingly parallel operations, and they have to be modified to support it if they haven't been already.
The move from 1 GHz Cortex A8 ARM to a 1 GHz Cortez A9, assuming Apple didn't spin its own core and is using the A9 core, you'll get a 10% to 20% increase in single-threaded ops per Hz. So single threaded apps should see that, not a 2x.
The really curious things will be if Apple implements independent power gating (both voltage and frequency slewing) on the cores.

iOS apps are already multi-thread aware and Apple began telling developers to think about multi-core way back in 2009 so hopefully the ramp up won't be too long.
Mostly I'm just looking forward to having 2 cores to split tasks, like the display mirroring, perhaps some multitasking as well.

Shrike's point was that not all tasks can be made multithreaded. If, for example, an app has to open a single file, or parse a long XML or Json resource (cough The Daily cough), it cannot split that work between threads, no matter how hard the developer tries.
Lots of tasks are similarly not parallellizable, and for those tasks, there is no ramp up possible - they just cannot take full advantage of multiple cores.

Yup. The dual-core will handle load (system throughput) better, but most CPU-bound apps won't be faster.
App startup/load times won't be much faster. I'm curious how the new Safari javascript engine improves performance compared to the CPU horsepower. Safari on both on iOS and Mac OS X has a ways to go. They still have low hanging fruit.
iOS background services shouldn't affect the foreground app as much.
I just wanted to set the expectation that 2x1 GHz multicore != 2 GHz uni-core. Most of the perceived speed improvements will be due to better Cortex-A9 performance. 15% to 20% better.

One won't usually see 200% speed with a dual core processor, but today's apps and OSs (incl. iOS) are massivelly multi-threaded. So dual core procs yield palpable performance improvements. Shrike is "off to see the Wizard" on his lowball perf. improvement estimates.
As for real-world uses of iOS, let's say the iPod module is running and Mail is checking for new mail, Skype is waiting in the bg while you're using Safari. You'll easily notice the practical improvement of dual cores.

If 256MB of RAM still provides a good performing iOS experience, why would they even need to change it? I could care less if there is 256MB or 4GB of RAM in a tablet, so long as the OS performs well.

More RAM will alleviate problems you probably don't blame on lack of RAM, such as Safari often refetching that entire page you were just reading when you return to its tab. It may only bother you a little, but adding more RAM would still improve the experience.

Ah, interesting. I've never actually experienced an issue such as that, being that I close a page when I switch apps. I know not everybody does that, but I hate leaving pages open.
It's weird, I understand that, but like GaGa said, I was born this way. It's a tick.

If you've never experienced that issue, then you must not use your iPad much. It happens to me DAILY and it's the most annoying issue on an otherwise well-performing device. The one thing the iPad needs is more RAM and 512 is barely adequate. They should have put in 1 GB.

Blame David Mitchell but I can't get past the "I could care less" comment. Do you mean you 'couldn't care less'?
meanwhile Safari performance with the anaemic cache is an iPad weak point that makes me wary about switching tabs. So yes. It is very much an issue with the iPad 1.

I guess I'll settle for 512, theres no way it only has 256 as quick as it was moving in engadgets videos. Everytime I add more memory to my computer it gets better. I guess since all people know is 256 in an ipad they have nothing to compare it too.

Try not to forget it's the same RAM as a 3GS, the phone apple is currently trying hard to toss under a bus.

Will the promised GPU and processor upgrades help rendering speeds on large pdfs in good reader, or is it based mostly on ram? Thanks.

I find it funny how to some speed and refresh are such an issue, like wise the attention given to specifications. For a vast majority of users these things are a non issue as these people are non technical or not tech geeks. We are not that far away from the day of the TRS-80, it is just amazing what new devices can do, but it is also a show of how society has changed, we want it now and things have to be done instantly. I would not call a page refresh a major problem nor consider one device better over another due to it loading faster, what matters is the entire package, the user experience and seamless integration between hardware and software, in other words transparency, the Apple products and echo system provide this through design.

Yes but when will these new iPods and iPhones come out? What will be the better one after that?

So are you saying that the ITOUCH 5 will or will not have the A5 chip? I hope so. Part of me doesn't however because while this will give developers a lot of incentive to make faster,more memory hogging games, it also means I will have to spent another $300 for the new idevice (when I just picked up this one less than a year ago) if I want to stay current with the best gaming That Apple has to offer. Im absolutely addicted to the killer gaming on this device so there will be no way around it for me. I will,without a doubt purchase it if it sports even an A4.1 processor! I only wish this upgrade was spread out over two years instead of one.Ha! I'm just thinking of how fast technology is moving now.Soon enough humans will be equipped with all kinds of technological devices straight out of the womb-HA!

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