Re: Modding a XpertVision 5900XT
Grechie, your 3D Mark scores look good for a 5900XT. There are lots of system and driver tweaks you can play with to get it higher (Vsync turned off is one, no AA or AF, overclock your cpu, not just video card, shut down useless programs in windows, enable fastwrites, sideband addressing, set AGP aperture size to 128, 256, or 512-whichever scores higher, etc)
Harl, flashing your 5900SE to a 5900XT should work as they are basically the same thing. However, I would click that link I posted and ask some people in the Guru3D thread.
Flashing video card bios to other video cards to improve performance can work if the bios's are compatible. There are some risks. Do your research to minimize them. It really helps to talk to someone who has already flashed a 5900SE or 5900XT.