It can be set in the Radlinker options. In the "Boot: BIOS Defaults" section, click use current after you have it set where you want it. The machine will then always boot at those settings. If you ever want to set it back to what it was when you first got it, click "BIOS Defaults"
I owned an averatec 6130-hs with a P4 and a 9600, although the stock bios clocked the 9600 at 350mhz core, and 202.50 for the mem. So I would say you could clock up the GPU to 350, but keep the mem to 202.50. The memory seems to be what fries easy, the GPU on the other hand does not.
The one thing I did notice is that the averatec had a real passive heatsink for the GPU, whereas ours has a flap of aluminum. That may be why they can run at 350.