I just wanted to summarize my experience with this.
I had a good working system with SME Server 6.01 set up on an MSI K7T266 Pro2 Motherboard, Athlon +2000 CPU, 1GB Kingston Ram.
The capacitors on this board were leaking so I wanted to move to Intel Board/processor. All other periphreals would remain the same, NICS, RAM, Video, drives etc.
Tried all of the recommendations in the thread to make this work and it would not. So, I tracked down another board (ASUS A7V8X-X) that would carry the original AMD processor and powered it up, and never had to change a thing.
The Intel stuff we were trying to use definately works, have since reloaded NT 2003 Server.
Thanks for the suggestions etc, but IME if you have a good working system and the board fails my experience was successfull by retaining the AMD architecture.
Dan