The user Skyscraper thinks an AGP Geforce 6800 GT or Ultra is the best choice if one wants to maximize the video performance using an an AMD 760 chipset motherboard or any other old non Intel chipset AGP motherboard for that matter.
It's possible that the Nvidia bridged cards can be made to work but in my short testing I did not manage to get them fully stable with the Abit KG7 or the Asus A7M266.
The AMD bridged cards like the AGP X1950 Pro were somewhat less problematic but I would still go with a non bridged card.
Using an Athlon XP-M 2800+, the KG7 and the Geforce 6800 GT @Ultra I had no issues with running Doom 3 v1.0 at 1024*768 using the Ultra preset. I find this kind of impressive for a motherboard chipset from year 2000.
I was going to mess around with my Socket-A motherboards and CPUs alot more but that project got sidetracked by life in the form of too much to do at work and I have not revisited Socket-A since.
New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.