Found this cool piece of software and thought of you guys straight away!!
If you cant over-clock your board,try and raise the FSB instead!!
A friend was running at 1000Mhz at 100FSB. He is now running at 1200Mhz at 120FSB. With just a 200Mhz increase he can definetly tell the difference.. Like a NEW pc all together!!
He did say it affected his on-board sound though (I dunno to what extent (Might require some tweaking))
http://www.softpedia.com/progScreenshots/CPUFSB-Screenshot-2678.html