Really need a little advice- PC is: HP e9120y/AMD Phenom II X4 910, 8 GB ddr3 (pc3-10600MB/sec)- but sitting on a 300 watt power supply and 4350-- Question is this: better power supply and 6850? or 6870? or just stick with a 5770 or 5570?? WOW addict, want to know what will work for CATACLYSM? looking at the power requirements on 68xx is lower, have only one PCIe x16 slot - so no crossfire in the future, mobo won't hack that... Thank you!! (Looking at Black Friday for the upgrades...)