Apple creates own CPU to power iPad

Written by Alex Watson

January 28, 2010 // 11:19 a.m.

Tags: #apple #apple-a4 #arm #arm-cortex #arm-vs-x86 #atom #bob-drebin #ipad #netbook #pa-semi #soc #tegra #tegra-2

As we reported earlier, Apple has finally launched its long rumoured tablet, the iPad. In most respects, the device is very similar to what the rumours claimed – however, perhaps the most intriguing part of the design is that the iPad will be powered by an Apple CPU.

Called the Apple A4, Steve Jobs referred to it only briefly in yesterday’s keynote speech, confirming it was clocked at a nice, round 1GHz and that the A4 is a system-on-a-chip with a CPU, GPU, I/0 and memory controller. A picture of the chip appears in Apple’s video for the iPad, and iFixit – the firm responsible for the teardowns you see of new gadgets – has some slivers of information on it, and a nice HD still.

Apple all but announced its intention to create its own chips when it purchased P.A. Semi in April 2008 and then became an ARM licensee. P.A. Semi was known for producing low power chips based on the Power Architecture (which has found its way into many devices, including the PPE part of the PS3’s Cell CPU). In addition to P.A. Semi, Apple also hired Bob Drebin who was the Chief Technology Officer of AMD and ATI’s Graphics Products Group.

It seems unlikely that Apple has invented something completely new with the A4, and while P.A. Semi’s experience was with the Power architecture, the iPhone, with which the iPad has much in common, uses an ARM CPU. It’s likely then that the A4 uses an ARM core – rumours reported by Bright Side of News and iFixit suggest that it’s the Cortex-A9 MPCore. This is the same ARM core used by Nvidia in its upcoming Tegra 2 SOC design (and it means our guess on Twitter that the iPad would be Tegra 2 powered is pretty close!) Little is known about the A4’s graphics, although as with the iPhone 3G and 3GS, it will be compliant with Open GL ES.

At 1GHz, the A4 is 400MHz faster than the ARM CPU in the iPhone 3GS, so it’s perhaps not surprising that videos of the iPad in action show an interface that’s snappy and apps that are quick and responsive.

Obviously there are still many questions to answer about the A4, but its appearance in a device aimed at the heart of the netbook market – currently dominated by the Atom CPU – is sure to make Intel feel nervous. Are you happy Apple is now in the chip business? Or should it have gone with x86? Let us know your thoughts in the forums.

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