I had a 386sx@25MHz too and I don’t remember it being that slow. Unless that demo has the detail cranked up to high or something like that. Although, like that first commenter I had a math co-processor, so maybe that helped.
Or maybe my memory is off and I made the window tiny.
Ew, no. Even 386DX-40 is terrible for Doom:
Doom timedemo 386 DX 40 MHz DOS PC
486SX-33 is certainly playable, but you really want 486DX2/66:
Doom Timedemo - 486DX2/66MHz
Edit: grammar
Edit 2: These videos are accurate, btw. I upgraded from 386SX-25 to 486SX-33 just for Doom while my friend got the 486DX2/66 Packard Bell. Envy.
Edit 3: My memory forced me to go back and properly designate the models.
I had a 386sx@25MHz too and I don’t remember it being that slow. Unless that demo has the detail cranked up to high or something like that. Although, like that first commenter I had a math co-processor, so maybe that helped.
Or maybe my memory is off and I made the window tiny.