Pls help me OC my sapphire x1600xt 256mb

As everyone here knows this is not a very fast card. Therefore, ive tried several times to overclock. But i can only increase a few Mhz from both core speed and memory speed before the PC locks up.

Im using a zalman cooler so cooling is not the problem. Has anyone OC'd a x1600xt succesfully? If so how? Please help me out guys.

Thanks in advance.

Mines the same, But i think theres volt mods for it if you want to overclock higher.

http://www.google.com/search?hl=en&q=x1600+volt+mods&btnG=Google+Search&meta=