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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