Overclocking the ASUS P6X58D-E was simple once I realized it didn't like the XMP profile of the Mushkin Redlines with the default BIOS v108. To keep the board happy I had to run the memory at 7-7-7-20, with an update to v303 it was able to run the XMP profile just fine. Manually setting the BCLK, CPU multiplier, memory speed, CPU/QPI/memory voltage, turning off Speed Step, and a few other minor settings were all that were needed and then some to get past 200 BCLK - the number needed to get 4GHz without the extra turbo multiplier on a i7 920.