Quote Originally Posted by slim142 View Post
I have 2 8800GT SC editions and I used Precision to overclock them. I select unlinked and I overclock my shaders from 1620mhz to let say 1630, however when I run 3dMark06 I still get 1620 (according to my logitech G15 and the on-screen option enabled). No matter what # I select, shaders stay in 1620mhz, WHY???
That's normal. The clocks are generated from the same crystal, and there are specific steps in which you can clock the shaders & the GPU Core & the memory.
Check this article/guide

P.S. And yes, use RivaTuner