C2D e6400 won't OC more than 2.67Ghz in Windows 7, BIOS allows higher.
At post i show CPU clock running @ 2.8Ghz (350x8)
Once Windows loads it clocks down to 2.67Ghz. CPU-Z confirms this, 2.67Ghz in CPU-Z as well.
I performed the overlock in the BIOS. I've turned off EIST speedstep, still no joy.
I've allowed Max Power Plan in Windows 7
I don't know where else to look... If my motherboard didn't allow that high of an OC then it wouldn't show that speed at POST would it?
You are correct in your assumption that, if the motherboard didn't support such an overclock, then you would have issues booting.
Perhaps, you can increase your CPU multiplier, and dial back the (( I forget the name of it )) setting you have set to 350, and let us know what that does.
I have had issues with using this setting to scoot up an overclock, rather than using the CPU multiplier.