Help overclocking E6600 on Asus P5KC

[Jamz]

Every time I try to overclock my E6600 on this board no matter what settings I've adjusted I either get "overclock failed!" message when system is trying to POST or I get these messages "Unknown CPU detected. BIOS update needed to unleash its full power. Press F1 to continue.", then after pressing F1 I get this message, "The file is possibly corrupt. The checksum does not match the computed checksum."

I don't have any problems though with running everything on default settings.

This is a brand new mobo that I installed yesterday. I updated the BIOS to the latest 0804.

I know this E6600 can at least do 3500 MHz as that was what I was able to get it up to stable with my last EVGA 680i mobo.

Anyone know what's wrong?



***UPDATE***


ok so I figured it out a little.... I realized that it was the RAM settings... apparently it'll only overclock if I set the RAM 1:1... it doesn't work with any other divider even if I relax the timings a lot.... so right now I have it set to 8 x 400 = 3200 MHz with the RAM running at DDR2-800. My Crucial Ballistix Tracer RAM is rated for DDR2-1066 though and I'd like to get it at least to run at spec.... but when I try to use any other dividers I get the overclock failed or unknown cpu messages and my computer won't POST.... I know this RAM will overclock to 1200 MHz with 6-7-7-18 timings, 2.2v because I had it at that daily on my old motherboard.

Also I noticed that when I check CPU-Z, Orthos and CoreTemp, CPU-Z reports the cpu frequency as 3200 MHz (as I set it in the BIOS) but Core Temp and Orthos show cpu freq as 3599 MHz (450 x 8). What's going on there?