I have an evga 7600gt and I know the card is already clocked high, but I wanted to get a stable overclock to the level of the superclocked or xfx xxx edition. I got the Zalman VF700 so the card is very cool, and very quiet, but I still can't get my memory to clock above 770.

Is their a physical barrier to overclocking the memory or is it just heat still?
Can you damage the card through testing in coolbits? for example, if I ask it to test 700 core, will that potentially damage the card, or is testing at any level safe?
Any recommendations, to safely get the memory faster?

The highest I've seen my core temps are 42 (after 3dmark06), so the card is cool right now and the clocks are at 598/760.

How are you overclockng this?

when using coolbits, you can choose to test your overclock..and if it is to high, your computer will freeze (not a bad thing in this case because by doing this it is preventing harm to your card) and then you will have to restart...or, you can have it automatically choose the clock that your card can handle stabely...do not worry to much though, because your card has a lifetime warrenty that covers anything but physical damage, so if your card fries, you will have a brand new one in 5 days

my advice - don't.

why is that?

Just be careful. If you don't know what you're doing, take Tedster's advice.