Apple's A6 Details and Timeline Emerge

MojoKid writes "For a CPU that hasn't seen the light of day, there's a great deal of debate surrounding Apple's A6 and the suggestion that it may not appear until later in 2012. The A6 is a complex bit of hardware. Rumors indicate that the chip is a quad-core Cortex-A9 CPU built on 28nm at TSMC and utilizing 3D fabrication technology. While the Cortex-A9 is a proven design, Apple's A6 will be one of the first 28nm chips on the market. The chip will serve as a test case for TSMC's introduction of both 28nm gate-last technology and 3D chip stacking. This is actually TSMC's first effort with an Apple device. The A4 and A5 have both historically been manufactured by Samsung."

Comments

Unbelievable

[Anonymous Coward]

Steve's not dead two weeks and already Apple fumbles the ball. STACKED chips? How is the next iPad going to be as thin as it can possibly be when they start stacking chips?

Quad Core In a Tablet/Phone?

[rsmith-mac]

I love my quad core desktop processor, but I find myself scratching my head at the idea of quad core CPU in a tablet. Even with iOS 5's enhancements there's no true multitasking in it or any other tablet/phone OS - every application is interacted with in a full-screen monolithic manner.

Dual core CPUs allow the OS to do one thing in the background and not bog down the device for the running application, but what on earth are you going to do with 4 CPUs when you can only interact with 1 program at a time? This seems like it would only be of benefit to games and a couple other niche uses, otherwise a processor with fewer cores and higher per-core performance like the A15 mentioned in the article would be far more beneficial.

Re:Quad Core In a Tablet/Phone?

[jpapon]

Just because there is only one app running doesn't mean it is running in a single thread. While most apps might not take advantage of multithreading at the moment, if quad core processors become the norm I'm sure you'll see them starting to use it. That is assuming that Apple actually put multithreading into their iphone SDK.

Re:Quad Core In a Tablet/Phone?

[Stevecrox]

For me it's more about the manufacturing yields, the article mentions TMSC are struggling with their 40nm production process and this thing is 28nm being released next year. From what I understand TMSC is being used to remove Apples reliance on Samsung, I wouldn't be surprised if this allows Samsung, etc.. to jump ahead as TMSC don't sound ready to mass produce the chip.

Dual core makes sense because of power saving issues, you can have one low clocked core which is enough for basic phone functionality which is turned off when you started using the phone. In this sense I could even understand a triple core chip, you would have one low power core for when the phones not being used, then when it is you can move OS/Background processes to one core and have a 3rd core for running the main process.

Surely a purpose built GPU would give far better gaming improvements than an additional A9 core.

Re:Quad Core In a Tablet/Phone?

[Graff]

Dual core CPUs allow the OS to do one thing in the background and not bog down the device for the running application, but what on earth are you going to do with 4 CPUs when you can only interact with 1 program at a time?

You do know that iPhone apps can do quite a lot in the background, even if only one app can have focus at one time, right? Right now apps are deliberately curtailed to only certain background activities because of the limitations of the amount of cores, adding in more cores and more powerful cores will allow apps to do more in the background.

The limitation of being able to interact with one app at a time is due to UI constraints. Even on a regular computer there isn't much case for multiple programs being visible to the user at one time. For the most part a user isn't able to fully interact with multiple programs at a time, the usual case is to view a document in one app while doing work in another. A better solution to this is to allow programs to share their display engines so that a single program can run and display documents from other programs while only having one program running at a time.

The model of one application running with a few lighter weight processes doing background work makes sense for devices with tight resources and that's the model that iOS is attempting to follow.

Re:Quad Core In a Tablet/Phone?

[perlith]

Maybe Apple has finally decided to support Flash?

Re:Quad Core In a Tablet/Phone?

[Crash Culligan]

rsmith-mac: what on earth are you going to do with 4 CPUs when you can only interact with 1 program at a time?

This assumes that iOS will only ever allow you to interact with one program at a time. This also assumes that iOS doesn't do so already—ever play music while working with another app? It's a question of controls, and finding ways to work with multiple programs that works for the users.

If I were doing it, I'd consider a "half-screen" mode where you can have two apps open, one on each side of the screen. But that's worse than Apple-armchairing, that's UX-armchairing. *shudder*

Re:Quad Core In a Tablet/Phone?

[Anonymous Coward]

One core for the OS, one for the apps, one for the antivirus and one for the rootkit.

Re:Quad Core In a Tablet/Phone?

[Graff]

That is assuming that Apple actually put multithreading into their iphone SDK.

Of course there's threading in iOS. There are examples to be found if you google for them.

Re:Quad Core In a Tablet/Phone?

[rust627]

And one core to rule them all .......

no, wait, wrong story ........

Re:Quad Core In a Tablet/Phone?

[Kjella]

The article is talking about things long in the past, I have a HD5850 in my machine that's almost two years old and built on 40 nm process from TMSC. That process has been fairly stable for a long time now even though it was a bit delayed and early yields weren't as good as hoped. Where they have really struggled is with their 32-34 nm - I don't remember exactly - process that should have gone into the last generation of chips. In short, they ended up simply skipping it since they were due to deliver 28 nm by the time it would be ready. And there's actually three 28 nm processes, LP, HPL and HP which you can call low, mid and high-power. LP is really just for support chips, but it's rumored that HPL will be used for the next generation Cortex and AMDs Southern Islands, while nVidia is waiting on the HP process for their next generation. For the GPU business it just means progress is slower - both AMD and nVidia are stuck waiting for TMSC. For CPUs on the other hand Intel and GlobalFoundries are heavy competitors - GF to take over the business while Intel only produce for themselves - but being a process step behind is like fighting with one hand tied behind your back.

Stacked Chips

[narcc]

I bet they'll try to patent this "innovation" -- even though they clearly stole the idea.

For goodness sake, Pringles has been stacking chips since the 1960's.

Re:Stacked Chips

[TheRaven64]

Pringles claimed that they were stacking cakes. They lost a court case in the UK over this a couple of years back - for strange historical reasons, you pay VAT on crisps, but not on cakes. Pringles had been avoiding paying VAT by claiming that, because they were made from baked dough, they were cakes and not crisps.

Re:Stacked Chips

[itsdapead]

They lost a court case in the UK over this a couple of years back - for strange historical reasons, you pay VAT on crisps, but not on cakes.

The strange historical reasons being that some bright spark thought they could be really clever by only charging VAT on "non-essential" items, thus creating endless work for lawyers and committees arguing over what was "essential".

...and as anybody who watches QI knows, the official definition is that "cakes" go hard when they are stale, whereas biscuits* go soft.

* That's biscuits as in British English, i.e. cookies or crackers - not scones (which I guess are cakes).

Doesn't sound true

[KClaisse]

Apple has already had problems in the past with low-stock at launch. Why would they risk having even worse problems using unproven tech at a fab they haven't used before? There's always problems with supply when dealing with smaller fab tech, which will probably be worse with 3D being thrown in.

Re:What is a 3D stacked chip for a fab?

[UnknowingFool]

From 3D stacked chip, I'm assuming that they'll be stacking multiple die on each other, like in an MCP.

Stacked chips having been happening a long time. The A4 and A5 are stacked with the CPU and the memory on top of each other. Technically there is no reason why they can't stacked CPUs on top of each other. Practically, I suspect heat is a problem.

The other part of the question - iOS - is it something that's as SMP enabled as OS-X is? From what I've seen of i-PADs, they are not multi-tasking OS's at all - all they do is save the state of an app once you exit it, and resume from that point if you return. If that's the case, how does multiple cores help for this case?

iOS is based on OS X which is based on BSD so yes SMP is there. Your knowledge about iPads is very out of date. The hardware itself is capable of multitasking as you play music while surfing web. The APIs that Apple exposes limits how applications access the multitasking. Fast-switching is the most common used version because most applications don't really need to keep running while not being used. However Apple provides seven different multitasking models in iOS 4 released more than a year ago.

Finally, Apple can make this chip even better for themselves by moving their macs and airbooks to this processor, so that they have just one CPU platform of their own, making it easier to have a common code base for their apps, like Safari, Mail, et al.

Except that ARM and x86 instruction sets are not compatible. You can emulate x86 in an ARM environment but it will be painfully slow. Emulating ARM in an x86 environment will work but there's no real point other than coding and debugging for something like iOS.

It is the GPU that wil matter!

[Bram Stolk]

Apple can afford to bring out iPad3 with a CPU that is not much faster than the current one.
What they can not afford, is stalling GPU performance.

If rumours are correct, and iPad3 will have a retina display, it will need a lot more shader performance to fill that screen with 3 million pixels. As it is now, it is hard enough to get 60fps on non retina displays with moderately complex OpenGL ES2 shaders.

Quad Core is not just for handhelds

[SethJohnson]

Apple has been twisting Intel's arm (that IS a pun) about power consumption and threatening to dump their chips in favor of ARM. Another way Intel limits Apple is that their product cycles are tied to Intel's product cycles, which constrains Apple to a parity with other laptop vendors. By moving to a homebrewed CPU, it would give Apple even more architectural control / freedom which would assist in differentiating Apple products from their competition.

Funny how it all comes full circle. Apple suffered from having its unique RISC architecture for many years. Then Apple conformed to X86 for just a few years and leveraged that to get enough marketshare that they can move back to an independent architecture again.

Seth