XFX 790i Ultra VS P5E3 DELUXE /WiFi-AP

Just as it Says...
What would you recomend for OC? and what CPU and RAM would OC the best to get 4ghz or more? I'm thinking about also getting the GTX 280 is this a good idea or is there a better on for cheaper or same price?
THanks in advance!!

Majore difference here is that one board is sli and other is crossfire. Thus if you want one you can't have the other. If you plan on running one card solution go with intel based chipest, in this case asus board

so based on getting a GTX 280 I should get the asus Mobo?