I have motherboard GF615M-P33 and 2DiMM slots. In both slots there is 2gb(total 4gb). So can i buy one stick of 4gb, remove the one stick of 2gb in one slot and put that one with 4gb to work with 2gb in the second slot (4gb and 2gb will both have same DRAM frequency at 1333MHz and same latency). Will my RAM work as 6gb and can i play games that needs 6gb like CoD:Ghost and later Watch Dogs and what are the risks?