Apple A4 vs. Intel Atom vs. NVIDIA Tegra : What's Inside Apple's New Processor ?

When Apple unveiled the iPad - its astounding rendition of the classic tablet - at the San Fran event yesterday, the company also, in effect, launched its newest chip powering the device: The Apple A4.

A Bit of History

The A4 is Apple's first self-produced chip. It was created by P.A. Semi, a design company Apple acquired for $278 million in April of 2008.

Prior to the A4, Apple used 3rd party processors to run its products. These include IBM/Motorola's PowerPC for the iBook, Powerbook and PowerMac (Apple's legacy products), Intel Core processor for Macbook, Macbook Pro, Macbook Air and iMac and ARM Cortex for the iPhone and the iPod Touch.

What's good about Apple finally designing its own processor?

By designing chips internally, Apple will have ultimate control over end-user experience. Instead of working around the limitations of a 3rd party chip, Apple can now custom fit a processor to exactly what's needed by a device

FYI: PA Semi's founder is a man named Dan Dobberpuhl, a StrongARM chip designer at DEC (a company whose semiconductor manufacturing arm was bought by Intel for US$700 million in 2007). StrongARM chips are similar to ARM-based processors which power the iPhone and iPod Touch.

The Apple A4 Architecture : What is it exactly?

Quoting BSN:

A4 is not a CPU. Or we should say, it's not just a CPU. Nor did PA Semi/Apple had anything to do with the creation of the CPU component.

A4 is a System-on-a-Chip, or SOC, that integrates the main processor [ARM Cortex-A9 MPCore i.e. Multi-Processing Core, identical to ones used in nVidia Tegra and Qualcomm Snapdragon] with graphics silicon [ARM Mali 50-Series GPU], and other functions like the memory controller on one piece of silicon - not unlike what Intel is trying to achieve with its future "Moorestown" Atom processor

In other words, much like NVIDIA Tegra (read TechPinas' Tegra discussion here) and the recently released Intel Atom Pinetrail Platform (read TechPinas' Pine Trail discussion here), Apple A4 is a chip that combines a CPU, a mobile GPU, northbridge, southbridge and memory controller all in a single package. PA Semi, as suggested by BSN's article, had nothing to do with the creation of the CPU because it merely integrated the pre-made ARM processor along with other components into what we know now as the Apple A4 chip.

Apple iPad runs on Apple A4 chip

Apple A4's CPU is an ARM Cortex-A9 MPCore CPU, which could be identical to the one found inside NVIDIA Tegra 2. Cortex-A9 is a multi-core processor that easily beats the performance of the single-core ARM Cortex A8 CPU of iPhone 3GS. As for the graphics silicon, A4 uses ARM Mali 50-Series GPU; ARM considers the Mali architecture as the world’s smallest yet most power efficient GPU, bringing hardware graphics acceleration even to the most cost-sensitive markets.

Power Efficient: Apple claims that iPad can get around 10 hours of battery life out of the A4, along with a full month of standby.

For the geekier ones, here's the architecture of the ARM Cortex-A9 MPCore CPU (I'm not sure though if this the exact architecture of Apple A4's Cortex-A9 as Apple could be using a custom variant of the CPU):

There you go. That's apparently what's inside the Apple A4 chip.
We'd love to hear confirmation from Apple though.

Stay tuned for more details. (Hopefully, benchmarks vs. Atom vs. Tegra.)

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  1. You don't know the core is identical. Apple is believed to have an architectural license from Arm, which would mean it could actually be a custom variant.

  2. Thanks for the additional info, Rob!

    I edited that part.

    I hope Apple could shed more light into this.

  3. PowerPC was never made by Apple. PowerPC was produced by Motorola and IBM. Apple moved away from PowerPC to Intel chip due to lack of progress on PowerPC by IBM.

  4. ^

    Not entirely true.

    PowerPC is a product of 1991 Apple–IBM–Motorola alliance and is widely known as an Apple chip.

    The difference between PowerPC and Intel Core is that Apple had almost nothing to do with the development of Core while it was hands-on with PowerPC.

    I think that's the point of the article.

  5. Apple has input into the later PPC chips only insofar as they were the biggest customer of them. The G5 was entirely an IBM chip, that they were pushed to design by Apple. Apple helped start PPC, but never had any real chip design experience--they were just a very demanding chip customer. There's a difference between that, and outright buying a design company.

  6. ^

    Thanks for the input.

    I've edited the article. I hope it's better now.

  7. Apple actually made a chip in the 80s:

    But this might be their first processor..

  8. Cortex A9 arch. Is available in dual and quad configurations, if apple dad used any of these, they would not stop boasting about it. I think that the recent claims that the A4 includes one customized core, in the sense; stripped down of redundant hardware. Which means it is a cortex A8 clocked at 1GHz by the use of the latest power management features apple seems to be focussing on.

    It would also contain the latest PowerVR SGX architecture which apple owns on the same die so as to make up the SoC along with other standard controllers and I/O.

  9. Actually, Apple designed g4's with Motorola and IBM. The G5 northbridge was also designed by Apple for the 970FX.

  10. Thanks for writing this I was really interested in see just what the A4 chip really was

  11. Only the Atom N280 figures are source: Linley Group.


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