Jon Stokes at Ars has an interesting take on the iPad’s A4 processor. He says it doesn’t have ARM’s next-generation Cortex A9 design which supports multicore processors. Instead, he contends that it is a single-core ARM Cortex A8 design which is along the same lines as the current iPhone 3GS, iPod touch as well as the Palm Pre, Droid, etc. As I watched the videos and read the reports of the iPad in action at the launch event, I was thoroughly convinced that the device was built on the out-of-order Cortex A9, possibly even a dual-core version. But it turns out that the the A4 is a 1GHz custom SoC with a single Cortex A8 core and a PowerVR SGX GPU. The fact that A4 uses a single A8 core hasn’t been made public, but I’ve heard from multiple sources who are certain for different reasons that this is indeed the case. (I wish I could be more specific, but I can’t.) Stokes speculates that Apple’s performance gains are likely the results of the chopping off I/O and camera components from the design (other companies get these generic chips with everything in them). He contends that the reason Apple hasn’t released any information on the A4 is because there is no “wow” factor to it. (10 hours of video on a bright 10-inch notwithstanding) NVIDIA was the first to announce a high production ARM Cortex A9 based processor which should be getting put inside the Boxee Box from Dlink soon.
