Ok, here's what I've found:
Go into true DOS mode. Use whatever batch file settings you like. In the
graphics options (inside game) shut off Paint/Skid marks. This really
increased the performance on my machine. The jerkiness with the short
tracks is virtually gone now and the speedways (C***te, Atlanta, etc)
are VERY fluid. I don't know why, but this seems to really help.
I've also found that using different memory settings in DOS will
sometimes result in an "out of enviroment" error when you try to set the
N2FX params...But they seem to work if you just type them in at the
dosprompt rather than use the batch file. I cant get fog to work with
the error though, anyone have any ideas?
My N2 3DFX machine is:
AMD K6-200 (non O/C'ed)
64Megs EDO
Diamond Stealth II
Diamond Monster 3D
etc etc etc
My gns3dfx.bat (or nas3dfx.bat) settings are:
SET N2FXAA=2
SET N2FXLOAD=0X20000
SET N2FXFOG=0.04
Like I said, if you get out of enviroment errors, just type these in
rather than using the batch file. According to the readme3d.txt, these
are the highest settings (for a 2mb texture mem card) and its really
starting to show the 3DFX well. I'll tweak with it some more and update
everyone, If I find out more. BTW, Changing the SET N2FXAA higher than 2
works, but I can't tell If its actually better, or just defaulting to a
setting of 2.