I'll agree with pairing it with the same CPU for compatability, but there is just one thing I'd like to know - why 2 CPUs? If you're building a server, then fair enough, but if you're building a gaming rig it's really not worth it. Many games these days still can't utilise 4 cores on 1 CPU, never mind having 2 CPUs with (up to) a total of 8 cores. Personally I think that if your goal is gaming, save cash by dishing out on a huge QX CPU and water cooling kit so you can overclock that bad boy even more. Or just get the CPU and use an air cooler without overclocking it.