Doom runs smooth at High level on anything that is as fast as or faster than a 486 DX4-75MHz, if you have a VLB or PCI video card. The game is capped at 35 FPS so you will never get 60 FPS on that using the default rendering engine.

You probably have PCI card - Diamond Stealth 2000 PRO . Without 2000 it's an ISA card. That would be a bottleneck for P-100 and graphics would be very slow.

kixs wrote on 2023-01-20, 08:52:

You probably have PCI card - Diamond Stealth 2000 PRO . Without 2000 it's an ISA card. That would be a bottleneck for P-100 and graphics would be very slow.

Is there a 4MB ISA Diamond Stealth? I doubt it.

appiah4 wrote on 2023-01-20, 08:49:

... The game is capped at 35MHz so you will never get 60 FPS on that using the default rendering engine.

35MHz would mean a cap of 35000000 FPS. It's rather 35 Hz (half of the refresh rate).

Falcosoft wrote on 2023-01-20, 09:31:

appiah4 wrote on 2023-01-20, 08:49:

... The game is capped at 35MHz so you will never get 60 FPS on that using the default rendering engine.

35MHz would mean a cap of 35000000 FPS. It's rather 35 Hz (half of the refresh rate).

I meant to say 35FPS 🤣 Fixed.

I've a Diamond Stealth 200 (S3 Virge based) in a Pentium Overdrive 83, so slightly lower spec then your rig and Doom runs fine.
I do find it takes about an hour to get back into Doom if I havent played in awhile but after that hour you no longer notice the blocky graphics, frame rate etc. As you said we are spoilt these days.

But you can check how far off the 35fps your running at.
Type: doom -timedemo demo1
After that runs you'll get
x gametics in y realtics.
and do the following caclulation, the answer is your frame rate
x/y *35

I'll try that when I boot next.

The difference between Low/High graphic detail isn't that big, but it's noticeable. The framerate slows down very slightly and isn't quite as smooth as when on Low. I'm guessing that's normal, but wanted to be sure.

Syntho wrote on 2023-01-20, 10:16:

I'll try that when I boot next.

The difference between Low/High graphic detail isn't that big, but it's noticeable. The framerate slows down very slightly and isn't quite as smooth as when on Low. I'm guessing that's normal, but wanted to be sure.

On a P100 properly configured, with a good PCI Card you need to get constant 35fps, and no difference in low/high

test fastdoom engine, use for example vesa or Mode 13h version

FastDoom. A new Doom port for DOS, optimized to be as fast as possible for 386/486 personal computers!

appiah4 wrote on 2023-01-20, 09:00:

kixs wrote on 2023-01-20, 08:52:

You probably have PCI card - Diamond Stealth 2000 PRO . Without 2000 it's an ISA card. That would be a bottleneck for P-100 and graphics would be very slow.

Is there a 4MB ISA Diamond Stealth? I doubt it.

They were. But very rare. He could be wrong with memory amount too 😉 Well, Virge chipset would have 4MB but it should run Doom without any slowdowns.

The only reason I can think of Doom being slow on a P100 is if it had a Rendition-based card, or an ill-advised ISA card of some kind, or a Sound Blaster Live eating the CPU for FM emulation, or there's no cache module.

appiah4 wrote on 2023-01-20, 08:49:

Doom runs smooth at High level on anything that is as fast as or faster than a 486 DX4-75MHz, if you have a VLB or PCI video card. The game is capped at 35 FPS so you will never get 60 FPS on that using the default rendering engine.

a p60 will actually show minor framedrops/stutters in some areas with a lot of monsters, especially spectres. should be smooth on a p100 with proper PCI video and cache though, unless loading some heavy custom WADs.

chinny22 wrote on 2023-01-20, 09:57:

Type: doom -timedemo demo1 After that runs you'll get x gametics in y realtics. and do the following caclulation, the answer is […]
Show full quote

Type: doom -timedemo demo1
After that runs you'll get
x gametics in y realtics.
and do the following caclulation, the answer is your frame rate
x/y *35

Low: 1710 904
High: 1710 1304

Good news though. In another thread I had an issue with my PC not booting. I figured out that the Turbo pins on the FPHeader shouldn't have been connected. Now when I switch between low and high it looks fine.

One issue I have though is that I'm seeing scanning lines in W95. They seem to disappear after a while. My other ISA card doesn't do that. Hmm. I guess it has to warm up?

EDIT: maybe with a full install of the Diamond software I could select its refresh rate and it'll look better...