I saw this posted somewhere, and I don't remember his name, but it really
works. Put these settings in the gns3dfx.bat or nas3dfx.bat file. It
really helps out the frame rate. 3Dfx N2 runs as well for me as the
Rendition version does.
SET N2FXAA=0
SET N2FXFOG=0.00
SET N2FXFOGCOLOR=0a8a8a8
SET N2FXLOAD=0x100000
SET SST_FASTMEM=1
SET SST_FASTPCIRD=1
SET GLIDE_SWAPINTERVAL=0
SET SST_SCREENREFRESH=75
SET SST_RGAMMA=1.10
SET SST_GGAMMA=1.10
SET SST_bGAMMA-1.10
SET SST_GRXCLK=57
GNS3DFX.EXE -3DFX