Apple iPad 2 : The Processor Preview

Over the next few days, we will be looking closely at what we can expect from the forthcoming Apple iPad 2 tablet which will be launched in just over 72 hours; we start our series by looking at the system on chip, the heart of the device.

The current iPad uses a 1Ghz Apple A4 system on chip which combines an ARM-based processor with a PowerVR SGX 535. We suspect that the new iPad 2 will feature technology inspired by the Cortex A9 application processor called the A5. Apple may choose to integrate Qualcomm's embedded mobile broadband modem, Gobi, in the system on chip, something both ST-Ericsson and Qualcomm have done.

Apple is likely to go for a dual core configuration based probably on the hard macro implementation ARM pushed out in 2009; at 800MHz, a power optimised dual core Cortex A9 would reach 4000 Dhrystone MIPS while sipping 500mW and occupying 4.6 mm2.

In comparison, a single core 1GHz Cortex A8 processor - used in the iPhone A4 - in comparison consumes 590mW, reaches 2000 Dhrystone MIPS, with an area with L1 cache of less than 4mm2.

In addition, Apple is likely to implement aggressive power saving techniques including the ability to dynamically change the clock speed of each core - depending on the load - and the ability to switch off one core completely.

Going for a dual core configuration will allow Apple to use the extra core when needed; the extra silicon will not add much to the price of the SoC itself (or to the average power consumption) and will allow the iPad 2 (and the iPhone 5) to be competitive with the rest of its competitors.