I'm running an ASUS A8N-SLI Deluxe mobo with and AMD 64 4400+ X2 (dual-core). I tried using the built in overclock feature in the phoenix bios, and it worked a time or two, but then the CPU fan kept shutting down at boot. Obviously this triggered the safeguard and wouldn't let the boot process continue. I eventually had to completely default my bios. Does anyone have any idea why this is happening? Thanks! BTW, I was running at about 10% overclock when I had trouble.

"built in overclock feature"? I suggest you overclock manually, like most of us do. - lower the HT multi to 4x - lock the PCI/AGP at 33/66MHz - lower the RAM speed to 166MHz - disable all Spread Spectrum settings - increase the CPU frequency to 250MHz - be prepared to increase the CPU voltage (vcore)

That's a whale of a CPU increase. Also, I'm assuming that my PCI/AGP is locked, because I have yet find a setting for it. Finally, it seems like it might be more productive to keep the RAM speed up a little higher and not have quite so much CPU frequency. Have you tested these settings yourself? I'm not doubting you, but this seems a little contrary to some things that I've read. Thanks for your help!

"Have you tested these settings yourself?" I just had a look & I should have realized that your board has PCI-E. No, I have not worked with that board or with an X2. You should overclock manually, don't use the percentage settings. Let me try again: - disable Cool n Quiet - if there are any Spread Spectrum settings, disable them - set the Overclock Profile to manual - set the HyperTransport Freq at 4x - set the Max Memory Clock at DDR333 - lock the PCI-E clock at 100MHz - increase the CPU Freq to 250MHz (you may wanna try this in small steps, 5-10MHz at a time) - be prepared to increase the CPU voltage if necessary

Thanks, I'll give this a try. As a sidenote, what exactly does spread spectrum do? Just curious.

Spread Spectrum has to do with RFI (Radio Frequency Interference) & it is supposed to be enabled by default as an FCC regulation. Basically, many electronic devices give off RFI radiation to some degree & some devices will interfere with other devices if they're placed too closely together. Spread Spectrum "spreads" that radiation over a wider bandwidth to keep the pulse spikes down, but doing so can also cause system instability, especially when overclocking. The thing is, enabling spread spectrum doesn't actually reduce the amount of RFI interference, it just changes the way it's measured. For example, a rectangle with a base length of 10 (bandwidth) & a height of 20 (pulse spike), still has the same area as one with a base length of 20 & a height of 10...the important thing is that the height (pulse spike) is lowered, & that's what the FCC wants.

"enabling spread spectrum doesn't actually reduce the amount of RFI interference" sorry, I meant the amount of RFI radiation