Two video card questions, please help!

[Zmaz]

I've got an nVidia 7600 GS in an ASUS A8N-SLI Deluxe mobo. I'm trying to overclock it, I've used both rivatuner and coolbits. However, no matter what clock speeds I set it to, even if I set it to 100/100 (Stock is 400/400) it still fails the internal test. Any ideas?

Also, I'm thinking of buying a 20" widescreen, 1680 x 1050. Would my 7600 GS be able to run games on it well? (BF2142, TR: Legend, Civ 4, HL:2 and CS:S.)

Thanks!
---Zac