I am using P5b-VM se Asus board with G965 chipset and drivers from msfn for ich8 on windows 98. I have GT6600 and also tested 6800 vanilla PCIe nvidia cards on it. infact i have 4 of these all pci. I used the 81.98 driver from nvidia and replaced the ini from a thread on this site into the extracted driver location on c: . This installed the driver without a hitch and i got some decent scores on 3dmarks. all 3d works and there is no video issue whatsoever. I am using core2 duo processor E5800 and also tested E8400 as i have 2 identical motherboards (1 for backup in case 1 fries in future.) do not use guru3d drivers they dont get full screen 3d acceleration
update, I was able to run unreal gold perfectly, I also ran revenant without any problems ( had to set to control speed ).. I tried viper racing and it would run the demo but the game would not work and sound was terrible (suspect my sound card drivers were the problem maybe ) , I tried caeser III and it crashed, I had selected the register on line button and it locked it up., rebooted and kept getting a rnaapp not responding and then a explorer this program has performed an illegal operation, repaired reg and still getting the same errors, could not even boot up in safe mode.. ? .. ugh... I usually clone my drive before messing around but I did not have a spare this morning.. guess i will have start from scratch again. as for the windows 98 plus screen savers ,, some would work, some would only work in software mode and some would only run with no color at all.
So in short, i suggest you all probably stick with the geforce fx or early series because of all the issues that are plagued with on windows 98 driver side which are not even worth it. even the early geforce 6 series like the NV40 agp geforce 6800 which was NVidia's last to officially support with their early and late win9x drivers; has a ton of issues with alot of games and being somewhat unstable.
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