i'm not sure how dual channel applies to 2gb of ram but for instance if you only wanted 1gb it would be more efficient to have 2x512mb than 1x1gb. what do you want 2gb for because it may be expensive overkill?
oh right at the mo i have pc2100 running in dual channel so ur syaing i cant get 2 more stiks to get 2 gig of ram cos my pc wouodnt be able to handle it
The less sticks the better. It will take the CPU less time to access if it only has to visit 2 sticks instead of 4. You want the lowest number of sticks possible, starting at two anyway so you can run dual channel.