I'm having some issues when overclocking a 7900GTX graphics card. Whenever I go even 1MHz above stock on either the core or memory of my video card, all OpenGL-based games get extremely artifact-y.
However, any D3D/DirectX game under WINE is fine, and Compiz Fusion works normally. Even Nexuiz is unaffected.

Here's a screenshot of Counter Strike 1.6 in OpenGL mode after I've overclocked my card:
http://img371.imageshack.us/img371/2792/16wuthi8.png


Doom 3, Warsow, and Alien Arena are even worse, but like I said, Nexuiz and Compiz Fusion (and all D3D/DirectX games) are completely unaffected.

So, what can I do to help remedy this problem?