Thanks taym.

I've been using a Samsung original 512MB stick of PC3200 that is new, and I tried a stick of TwinMOS el-cheapo PC3200 from my old PC that I know works. The Samsung stick seems to work alright in my other PC.

The only other stuff that is plugged into the board is an old Matrox G400 16MB AGP which I know works, and nothing else. I think its basically either the chip or the board which is dud, and I have no way of knowing for sure which.

Meh, I took a chance and filed a DOA RMA on the board. Fingers crossed it will get sorted sharpish.