Question about dual channel memory

I have the Asus P5k Deluxe. If I run 4gb of ram in dual channel is it better than haveing 6gb of ram with all four slots filled? 

if you fill up all 4 slots, it will still be running in dual channel. just make sure that the ram has the same cas and the same frequency. and generaly speaking, more ram (size wise) is more important that frequency and latancy. the only time it will not be running in dual channel mode is if you have 1 stick, 2 sticks in the impropper slots, 3 sticks (one pair will posibly be in dual channel, depends on the memory controler of the MB).

if you are keeping your old ram, i sugest buying the same brand with the same exact specs. same model if posible. if its not posible, take your old ram and put it in one set of dims, and the new ram in the other set. (exaple: old ram in both yellow dimms, and new ram in both black dimms)

just keep in mind, to get the full benifits of 6 gb of ram, you need to have a 64 bit os.

I have 2x2gb sticks and 2x1gb sticks. Will that effect anything?

if you want to stay dual channel, you would need to get another 1gb stick and make sure the 2gb sticks are in one bank, and the 1gb's are in the other. to be honest though, ram is so cheap now, i would just throw out the 1 gb stick and get a 4 gig kit (2gbx2). then you would have 8 gigs still running in dual channel

Wait a sec here. I have two 2gb sticks and two 1gb sticks so all four slots are filled up. Why would I need to get another 1gb stick? I would then have too many sticks. I don't quite follow you on that part  :/

oh, im sorry. i thought you had two 2 gig sticks and one 1 gig stick.

running with 6 gigs your still going to get dual channel. and 6 gigs > 4 gigs. just make sure that the sticks are in matching banks and all will be good. (2 gig sticks in gold dimms and 1 gig sticks in black dimms or visa versa)

Thanks ztrain you have been very helpful! Now I have a simple question about RAID that maybe you can answer. Since I only use one hdd do I need any RAID drivers for my motherboard?

nope.

and you can have multiple hdd's that are non raid without raid drivers :)

Thanks a bunch ztrain!