Quote Originally Posted by chrisf6969 View Post
Upgraded to 1006 & tried other suggestions, still craps out around 4Ghz. vdrop is only about .02 now vs. .10 before. I guess I got subpar 8400 that just doesn't want to do 4Ghz.

As for the sound, I've tried disabling spread spectrum, changing PCIe speed, unplugging USB mouse & camera, etc. None of that helped.

I've got almost everything disabled in the BIOS (onboard sound, onboard firewire, serial port, etc..) So I though that left the GigaLAN as possible problem. So I tried changing Marvell Yukon's max IRQ requests from 5000 down to 2500, to see if that would make a difference, didn't seem to help. I also manual set it to full duplex 100 (I don't have a giga router). Any other ideas, I'm thinking about RMA'ing the motherboard as I can't think of anything else that could be causing it. I tried 3 different sound cards. (Audigy LS PCI, Soundmax onboard, & X-Fi PCIe)
Have you tried other multipliers?

I have a E8400 (+ P5K-E) wich is also a bad one for 4GHz and I tried it also in a P5K Premium system with watercooling on it. Nothing really helped.
I'm using mine right now with 4GHz @ 1.41V "cpuz" (1.4375V bios) to keep it barely stable, and with a x8.5 multiplier. At "x9" it's Orthos unstable and I have sound problems too with my X-Fi at that configuration.
I tried also other multipliers but I had no low voltage good results either.
I don't think it's the motherboard, ram or settings, it's just not a good one for overclocking...
With so many good cpus out there, i guess eventually someone have to take the weak ones, it's just bad luck...