The Pro cards have faster RAM and the GPU cores are clocked faster as well.
The 9800 Non-Pro will be faster than the 9600Pro. The 9800 has a 256 bit memory bus path while the 9600Pro has a 128 bit path and the 9800 has 8 pipelines, where the 9600Pro only has 4.
Clock for clock the 9800 (R350) versus the 9600Pro (RV350) is about 50% faster.