Originally Posted by un-nefer
p67 mobos are better, but only because of the new CPUs they support, which are faster.
The only real issue with p67 is the limited number of pci lanes and the fact that even though most of the p67 mobos have two or more full length pcie slots, all those pcie slots are not all 16x, or even 8x, the 2nd pcie slot on the large majority of p67 mobos is actually only 4x.
So if you want to run sli or crossfire on a p67 mobo, you're better off buying a dual gpu card and putting it into the proper 16x slot.
Since you already have 2x single gpu cards, unless you seell them and go a dual gpu card, you'll need to buy one of the few p67 mobos that actually supports 8x/8x configuration - don't just assume it supports 8x/8x configuration because it has two full length 16x pcie slots, or you might end up buying a mobo that will only do 16x/4x.
The middle end and higher boards will be 8x/8x. There are 2 boards that are 16x/16x, this is accomplished via the NF200 chip on the Gigabyte GA-P67A-UD7 and Asus Maximus IV Extreme. Now the difference seen between 16x/16x and 16x/16x via NF200 will be maybe 1-2 FPS if that. The difference between 16x/16x and 16x/8x or 8x/8x is maybe 4-5 FPS. Yes he could sell the dual GPU cards for a single card with dual GPU's but why, there is really no point.
I would also say to the OP, depending n what you currently have now GPU wise. It may be better to upgrade GPU's at the same time you upgrade your CPU. Go P67 you will be better off in the long run.