You might have said this in a previous post but did you try new bioses for both the card and the mobo? The card might not have a new bios but sometimes companies do release them.
I know asus released a new bios a while ago for my mobo that added special geforce 4 support. They didn't list what that is exactly but it was listed in the readme. Have you tried checking for emi? Try changing the spread spectrum control to on in the mobo bios. Just a hunch but you never know. It wouldn't explain why you only get flashing in direct3d, however. Strange problem.
Gehenna_CA, Stormtrooper of the Doomed
AthlonXP email@example.com with Swiftech MC462
Asus A7M with 768mb DDR333 Ram
Visiontek Geforce4 Ti4400@305/650
Pioneer Slotload 16x DVD-Rom Optowrite 40x12x40 CDRW
20gig 7200rpm ATA100 HD, Philips A.E.
19" Daytek Perfect Flat, Inspire 5300s
WinXP PRO/w SP1