I have 2 PC's.
Asus mobo with 2x512 (3 slots available) running dual mode
Aopen SFF with 2x256 (2 slots available) running dual mode
I purchased a stick of PC400 512mb from ebay, inteneding to whack it in the Asus, in slot 1, and put the 2x512 in the other 2 slots, and swap the 2x512's over to the SFF>
Put the single new stick in the Asus to check it with nowt else in it, and Windows booted half way, then rebooted my PC.
Then I had a Missing File error on trying to boot up!!
Put the original sticks back in, crossed fingers, XP repaired itself, back to normal!
Presumed it was faulty, gonna send it back.
But for the effort of trying in the SFF, I thought I'd give it a go.
Booted fine. Ran 3d mark 2001 for an hour no hassle, ran Mem test, good as gold!
So put one of the sticks of 512 from my Asus in with it, for dual ram mode, sorted!!
Put the other 512 back in my Asus, with the 2x256's and thats fine too.
What is it with some ram...it wont work in certain mobo's at all? Nearly cancelled the entire Ebay deal and started over...no need now.