Currently I am running two 5770s in Xfire and want an upgrade. The CPU is a OC'd Phenom II 955 BE @ 4Ghz with 16GB of RAM. I was thinking two 7850's might be slightly to much power for my CPU and the 7790s in Xfire seem to be, for the most part, on par with a single GTX 670 which may be a great fit for the CPU. Any advice or other things I should know about? Leaning more towards the 7790s.