I have E6600, DP965LT Mobo, 4gig DDr2 800 mem, GTX 260
When I overclock CPU t0 3GHz passes tests doesn't get too hot. Crysis benchmark gives lower FPS. When I underclock CPU to 2GHz gives higher FPS than stock. Whats going on. PCie always at 100MHz.
Hmm what power supply do you have?? in some cases when a task requires both gpu and cpu and theres insufficient power to supply both components, one component gains less power, in this case your cpu when overclocked demands more voltage resulting in the gpu is running on a lower clock since theres insufficient power....This happened to me when i oced my 950 with a dodgy power supply and powered a 6950. either its this or what xtreme5 suggested, a bottle neck.