9600GT(s) should be able to overclock to around 750/1800/2100 or above with relative ease.
And the card isn't too shabby, 3 years down the road and it still does the job if you are gaming on low resolutions or don't mind lowered details. It even beats the Radeon 5570, albeit the lack of DX11 support.
By the way, is full caps really necessary?
9600GT is about on par with GT240. What about the other specs? tell us your FULL specs first... including monitor and budget.
You want a suppeeeer cheap card? I can point it to you but I'm not guaranteed about it's performance...