I have an Abit IS7 and I have a stick of 256 ddr400 Kingston value in dimm 2 and dimm 4 spot. They are on dual channel. If I were to add a stick of 512 (same kind has my 2 sticks of 256) in either dimm 1 or dimm 3 would I still have dual channel ram? Also will I have any compatibly problems?