For people who have compatibility issues/overclocking problems with their P5Q,P5Q-E/P5Q-Pro/P5Q-Deluxe and P5Q-Premium boards should check this out.
http://www.xtremesystems.org/FORUMS/showthread.php?t=200109
http://www.xtremesystems.org/FORUMS/showthread.php?t=200109