I already have 2- 1gb memory chips (DDR3) and was going to purchase an additional 2 - 2gb chips. (for a total of 6gb). should I just match slot colors with chip size? ie.., slots 1 & 3 for the 2gb chips, and slots 2 & 4 for the 1gb chips, or should I do 1 & 2, and 3 & 4? Is there anything I should be aware of (other than switching to Vista 64)?