Wow. My first personal PC has a GeForce4Ti4400 in it, with a XP1900, so the score of 1800 seems VERY low (I get about 9500 with
no OC'z, and 10175 with the
OC listed in my sig).
I would be guessing that the problem lies with the heatsync, but since you cleaned it off, that doesn’t seem to be the suspect. DO you have a thermal temperature monitor, such as a DD5 or a CompuNurse, or some thing from Radio Shack? Maybe it's just getting too hot... I had a problem like that with my GeForce4Ti4400 (Hence the current clock speed). If I take it faster, I can't play
any games at all, and I get blank screens every so often.
My guess, the heatsync on the RAM and possibly on the GPU are just not big enough. Maybe I am wrong though.