Thanks. I got everything set up today, and I seem to either be having a problem or just getting really lucky. The temperature of the first core (read from multiple programs) is a constant 42C, which seems like a sensor issue. The temperature of the second core varies from 30C to 40C depending on the load. It only rises to over 40 under a Prime95 small FFT torture test. Although I'm using my modded heatsink, this just doesn't seem right. I couldn't find much on Google, either.A quick google search gave me this: http://forums.hexus.net/pc-hardware/110267-c2d-overclocking-guide-beginners-p5k-add.html
It's been a while since I've used S775, but you'll want to make sure the PCI-E Clock stays at 100mhz. Also try to used "unlinked" overclocking mode, it saves you having to change the RAM dividers all the time.