tegrady wrote on 2021-05-01, 13:49:

I have a Windows 98 SE system where I am running Quake v1.06. […]
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I have a Windows 98 SE system where I am running Quake v1.06.

Specs:
Pentium 3 1000mhz (133mhz bus)
512mb RAM
Voodoo3 3000 16mb
Sound Blaster AWE64 Gold

When I run quake.exe from within Windows 98, the timedemo demo1 test gets about 37fps. However, if I run quake.exe from pure DOS mode (not DOS while Windows 98 is still running), I only get about 15fps.

I swapped in a newer ATI card and got 30fps in Windows 98 and only 14fps in pure DOS.

I would expect Quake to run faster in pure DOS as it is a DOS game.

Any idea what is going on here? If so, is there any way to fix it?

Thanks.

Drivers under Windows usually enables write combining (WC) of linear frame buffer(LFB) that means a lot for DOS games that use relatively high resolution VESA 2.0 modes. Most BIOSes do not set WC flag for LFB region so you need to use special utilities under DOS such as FastVid or MTRRLFBE.
http://rayer.g6.cz/programm/programe.htm#MTRRLFBE
Ps:
Try it without EMM386 or similar memory managers that put your CPU into V86 mode.
You can also try to set vid_nopageflip 1 in Quake's console. This usually disables vsynch and speeds up rendering somewhat. Though this setting has nothing to do with DOS/Win9x speed difference.