I have 2 x 1gb RAM sticks, and I want to upgrade to 3gb. If I upgrade to a set of 2 x 512mb, will it run in dual channel? I'm not sure how it works when you have four sticks. Do all four need to be the same or do sets of two just need to be the same?

I don't really feel like spending money on an extra gig which won't do much, so don't try to convince me to unless it won't run in dual channel.

Some mobos do dual-channel with mixed memory. Look up your mobo manual.

What's the upgrade goal?