An older system: AGP1 or PCI

I'd like to buy a new video card due to compatibility problems with XP.
Too many crashes due to 3dfx Voodoo Banshee.
Tried all drivers available for update, no joy.

It's an old Tyan Tsunami mobo that only has an AGP1 port.

Would you recommend another AGP1 or should I switch to a PCI?

Thanks