I just assumed that meant they were going from dual-core Cortex A9 to quad-core A9, and from dual-core graphics to quad (like what the A5X in the new iPad has now). Is there some other way they could've doubled the CPU/GPU performance? I kinda doubt they went to Cortex A15 CPU cores, although that would be freaking awesome.
It is unclear how many cores the CPU has. The performance improvement may come from something else also, like clock speed and other design changes.
I think the GPU cores may have increased. I am not sure. I'm sure other sites will cover.