I have a system that seems to be rock solid except for this one little prob that my Voodoo 5 5500 AGP will not run Direct3D for more than a few minutes before freezing. Glide and OpenGL are 100% rock stable. A strange thing is that if i put the card into single chip mode for Direct3D, it becomes 100% stable and will run 3Dmark 2001 for days on end. What could be causing this problem to only be evident in Direct3D mode and not Glide and OpenGL using both VSA chips?

System Specs
MSI 6163 Pro Rev2 (i440BX) with latest 3.10 BIOS
384MB PC100 SDRAM (CAS2 but running it at CAS3 to maximise stability)
3Dfx Voodoo 5 5500 AGP (BIOS 1.06) with official Win98SE 1.04.00 WHCL drivers
Matrox M3D (PowerVR PCX2) with latest drivers and D3D disabled for this card
SMC 1211 NIC
235Watt PSU (potential prob?)
Windows 98 SE with all patches and updates applied

I have removed the M3D to eliminate that as the cause and the V5 still locks in dual chip mode without it. I have also swapped in a Voodoo 4 4500 and that card was rock solid in this PC.

How do i get the dam thing to run in D3D with both chips enabled without locking up?