Mmmh... I guess the biggest effect would be on memory bandwidth increase. There's no pixel pipelines unlockable in 7600GT, and the core can only do so much if the textures get bottlenecked to the memory.
I run my 7600GT on about 722/1740 MHZ for core and memory respectively, which is a huge increase from the default settings, which are on 650/1600 MHz on this card, but it's from XFX and it practically has factory built voltage mod and other fancy stuff...and I believe it is a positively flawed card to boot. Funny detail and a stroke of luck, the card is supposed to be an "XFX GeForce 7600 GT XXX-edition", but on XFX's pages they say that those cards are supposed to have frequencies of 590/1600 MHz. So I've got 60 MHz extra from the promised frequencies even on default settings, and as the card seems to be particularly good to overclock I really got worth my money on this one.

I believe stock 7600GT has frequencies of 560/1400 MHz per core and memory... so if you compare stock GF7600GT and my anomalous turbo-version, mine has about 24% memory bandwidth boost and about 29% core speed boost, assuming that core speed is directly proportionate to the core frequency and other variables remain the same. The effect might not be cumulative for FPS rates, but it does increase 3DMark results where 3D abilities are concerned. Don't remember the exact ratios, though.