Since AMD MBs are dual channel RAM access, most would opt for either a 4gb kit (2x2gb), or, an 8 gb kit....(2x4gb)...
I suppose you could get a 2x2gb kit and a 2x1gb kit to total 6 gb, but, now all RAM slots are full, leaving no upgrade....
Do not get a 6gb triple channel kit (3x2gb)designed for the X58 mainboards
Actually, you think there two would work?
2x2gb kit -- PNY Optima MD4096KD3-1333 4GB Dual Channel Kit DDR3 1333 MHz PC3-10666 Desktop DIMM Memory Kit
2x1gb kit -- Kingston ValueRAM 2 GB 1333MHz PC3-10600 DDR3 DIMM Desktop Memory KVR1333D3N9/2G