Thanks for the welcome/reply
My
Mobo is a GeForce6100SM-M. I'm not sure why it is capped at x8, I'll have to find that out. However, I may be wrong as it could be a different model to my
Mobo.
As for the clock speeds:
7600GT (256mb)
Memory Clock Speed 1400MHz
Ramdac Clock Dual 400MHz
7600GTX (512mb)
Memory Speed: 800MHz
So I take it the 256mb one is, in fact better. Great

(If I'm reading it right, anyway :P)