Cross
Fire
And you can get the 1333 Quadpumped bus with the Q6600 as well, just put the FSB on 333 and it will run a 1333 Bus. And the Processor itself will then run just under 3Ghz (2997Mhz --> 2.997Ghz)... Cool èh ^^
Or if you put the multiplier at 8 it will run 8 * 333 and then it will do a 1333 Bus as well as running 2.66Ghz

Or if you up the FSB to 350 it will be running a 1400Mhz Bus and the processor will run 2.8Ghz... That might be a nicer overclock, less hot but fast.