PUNKtotalled,
As far as I know it is possible to use XP's on a dual board,
a friend has dual 1900+ XP's on a Tyan Thunder board.
I think the difference is support, I.E.
AMD will be a little more cooperative with supplying the tech support if you say you are/were running MP
rather than XP chips,
The friend has two sticks of 512 Meg ECC Registered RAM.
It's set so each CPU has it's own stick theoretically
(meaning one stick in dimm1 one in dimm3)
I believe the chips have their own bus to the northbridge
Anyway
just a thought
BTW good reads
Here