I have just built a machine using GA-7DXR (check my sig) and I bought 3*sticks of crucial PC2100 256Mb and Windows 2000 couldn't complete the final parts of the installation, it would hang. Took 1 out and all is fine. Saying that Gigabyte UK told me they knew of no problem using 3 sticks, but it definitely didn't work on my machine.
Hope that helps, If you have any more questions about the board just ask, and what a great board it is.
Tell me if your going to use one as I found there is a few things you have to do to start with, the board seems to be set to boot from the backup bios first.
Hope that helps.