Dual channel or not?

My daughter brought me her vista box because it of course is really slow. So I'm rebuilding the drive and installing XP Pro. Acer only put 1 stick of 512MB memory in it. I bought 2 GB to help with the speed issues. This thing looks like it has dual channel memory. I say that because there are four memory slots. 2 of one color 2 of another. It would seem that Acer crippled this thing by not taking advantage of the feature. I installed the 2 gigs as if it were dual channel. 1 gig in slot 2 of blue 1 gig in slot 2 of green. My question is what effect will it have if I leave the original 512 stick in it as well? I mean if it is dual channel she's got 2 gigs set up to use it but then the other channel only has 1 stick in it so that disables dual channel for that slot. Will dual channel still work for the 2 gigs I just put in it? Or should I just take the 512 stick out. Or I could go get another 512 stick and add that to the other channel. I just want to send her home with this thing right. If it means anything the processor in this box is an AMD athlon64x2 4000+ This thing should be screaming along not taking 10 minutes just to boot.

Dunno about your mobo - on mine the dual channel slots are the ones with the same color.

Oh, and dunno what speed your memory is, but if you mix chips of different speeds, everything will run at the slowest speed. Check BIOS and see what speed it has set - or use CPUID.

same channel slots are the same color so either use two blue or two green

do not use the third stick, by putting that in you are forcing all ram run single channel

two gigs of ram should be more than sufficient for most normal use and is a big upgrade form 512 so just leave that be.

as to the slow boot delete all partitions on drive reformat (not the quick option) and do a fresh install of the os

if you have a copy of vista then don't' waste your money buying xp just install vista and the appropriate updates and you will be fine.