Here's an interesting thing with the RAM slots; where you place your RAM will dictate the RAM speed. For example, if I place a stick of double sided RAM in DIMM1, I get DDR 400. If I add another stick of RAM in DIMM2 or 3, I still get 400. But if I place those same two sticks of RAM in only DIMM2 and DIMM3, I would end up with DDR 200 speed



Link: PimpRig