Itll be the 1200 Duron is too fast for the Voodoo1, there are only a few select cases where a Voodoo1 has been shown to work correctly with CPUs above 450-500 Mhz and even 450 is a bit too fast. I personally never put my V1 into anything above 300Mhz due to the known issues with fast CPUs.

I had no luck with Voodoo1 on Athlon systems, even when the cpu was downclocked to 500mhz on a 100mhz bus, I got lockups with checkerboard pattern. This was on a Via KT333 chipset. Only by disabling cpu cache were the lockups resolved, but then the cpu was too slow to run 3d games at playable fps.

One question i have a p3 800 with 133 fsb so if i go to 100 fsb it will run at 600. So can i expect to run games without issues?

I did some tests on my system and i got to following results. I used a p3 coppermine 1000 and 800 on a via 133pro chipset. I ran 3 games for test. F1 racing simulation for win and tomb raider and whiplash for dos.

F1 ran without any issues with 750 mhz @100 FSB, but tomb raider and whiplash crashed on 3dfx sign. Than I tried 600 mhz @100 FSB and the same, crashes for tomb and whiplash. on 3rd attempt i used 500 mzh @66FSB and than they ran also without issues. Maybe a BX440 board is more foregiving and you can run higher frequencies.