I am currently running 1gb x 2 (2gb) OCZ DDR 400 and want to upgrade to 4gb. I am running windows vista 64 bit and 2gb is not enough. My computer was originally running xp and then I added vista 64 bit in a dual boot config, and now I am using windows vista as my main OS. so my question is what is the best way to upgrade my memory. Its running in dual channel mode on my DFI LANParty UT nf4 sli-dr expert motherboard. soo if i add 2 more 1gb sticks into the other 2 slots, will the 2 sticks i have currently still be running in dual channel mode, or will everything be running in single? and should i try to get the same brand?