I also had the same question. I read at the Mushkin board that you could still run dual channel with the 2 256MB DIMMs as one channel and the 512MB one as the other channel, but I'm not sure if that's correct. Also, the ABIT manual says that for PC3200 and up, you can only use two DIMMs. Has anyone else successfully used 3 DIMMs higher than PC3200? If so that's great, since that means I can keep my two sticks I have now and upgrade to 1 GB in the future. Even if I lose dual channel, I don't think that it's really that much of a performance increase on an AMD platform.