Minimum CPU requirements

It would be cool if toms had such a chart... But anyways, am looking to move from my gtx260+ to a 6850 (to crossfire down the road, along with a new mobo) and seeing as that performance is pretty darn close to a 5970, I feel my unlocked 440 might prove to be a bottle neck. What is the minimum cpu (please suggest both amd/intel if applicable) to not bottle neck a 6850 xfire config.


Thanks in advance!