I have cured these problems on my system by switching my mouse from
a Com port 1 to a PS/2 port!
My system was:
Quantum Design MB, Intel 430TX chipset running at 75MHz
Intel 200MMX running at 225MHz
96MB ram
Stealth II - using, runs fastsest
Monster 3D II - slower, textures more washed out & blurry
Logitech Mouseman+ on Com 1
My mouse was difficult to use in the menus: jerky, and I had to
hold the button down a long time to get it to activate menu choices.
The framerate was smooth only if I left the mirrors off, still some
slowdown on the front straight & coming out of the pits, in 640x480.
I installed the demo on a friend's system that had the same motherboard
at 75MHz, a non-MMX P5 at 183MHz, 40MB ram, & a Stealth II. It ran
much smoother on his system with all graphics on at 800x600!
I reduced my system memory to 64MB, which helped a little (TX chipset
cannot cache more than 64MB memory), & a bench-mark program showed my
memory to be 10%faster now. Then I realized that the only other
difference in our systems was his PS/2 mouse. I put my mouse on the
PS/2 port, & disabled the com1 in the M/B bios.
Now the mouse is very smooth in the GPL menus, & much easier to use
in F1RS menus also! The framerate in GPL is very smooth, all graphics
maxed out, at 800x600, even rolling out of the pits. It could be that
the demo is not well optimized for a serial mouse, or it could be the
IRQ levels involved, the Com1 was IRQ 4, and the PS/2 port is IRQ 12,
so the PS/2 port will have a lower priority for getting read by the
system.
Hope this helps somebody out!
"Feel Lucky, Scubaboy?" - Discovery Channel, Shark Week, 1995