OCing GPU

[JoshSB]

I am attempting to OC my 7800GT with RivaTuner, so far I can get it to 480/1129 with no problems, looking at other peoples configs I have noticed the Core clock and memory clock have to be relatively in line on rivatuner, is this true or am i imagining it?

Thanks, Also, aything beyond 480 shows up weird dots of light in 3dmark05 on the firefly forrest test.