Yeah, from the looks of it Apple is running some seriously beefy graphics hardware that somehow sips power. We know the CPU is in-house, but what about the GPU (which IMHO is the bigger part of the equation).

The A4 is an System-On-Chip, so no separate GPU.

From http://news.cnet.com/8301-13924_3-10442684-64.html :

  By definition, the A4 is a system-on-a-chip, or SOC, that
  integrates the main processor, graphics silicon, and other
  functions like the memory controller on one piece of silicon...