Two months of speculation is over with the news that the iPad's much vaunted Apple A4 chip is an ARM Cortex-A8 with an Imagination Technologies' PowerVR SGX 535 plus 256 MB of RAM.

Apart from the uprated clockspeed of 1 GHz, that's effectively the same nuts and bolts as an iPhone 3GS or third generation iPod touch, although they're downrated at 600 MHz.

Of course, there also seem to have been various tweaks and optimisations applied, which is why the iPad is reckoned to between 1.5 to 3.9 times - or roughly twice - the performance of the iPhone 3GS, despite its larger screen resolution.

According to David Carey, veep of technical intelligence at UBM TechInsights, it has to do with the type of RAM used.

It processes data in 64-bit chunks meaning that you can move more data more quickly, as long as the transfer process is well structured.

[source: AppleInsider, Wall Street Journal]