tell you what...
Before you go all out on this card, run 3dmark2k1 with that card... I'd like to know if you get ~4k or ~7-8k...
If you get ~4k, you have a 64 bit version which you will not have fun OC'ing with, and would not gaming wiuth it either... compared to the true 128 bit variety at least...
If you do have the 128bit version, then you have some headroom for improvement...
If you have the 64bit version... well, um, you could probably get $50 bucks for it, turn around and buy a GF3 for $50 and enjoy twice the performance and much better shader capability...
My $0.02...
