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Rugxulo

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Usono,
11.01.2026, 20:06
(edited by Rugxulo, 11.01.2026, 20:18)
 

Doom: DJGPP vs Watcom vs. Digital Mars vs. CC386 (Miscellaneous)

Doom: DJGPP vs Watcom vs. Digital Mars vs. CC386

* https://youtu.be/_7dkppo9VC4?si=73ryTdlN4Z6CQTvW

* https://github.com/FrenkelS/djdoom

Guti

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12.01.2026, 17:08

@ Rugxulo
 

Doom: DJGPP vs Watcom vs. Digital Mars vs. CC386

Very nice. Surprissed me how far DJGPP is. I thought OW will be better.

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RayeR

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CZ,
13.01.2026, 22:43

@ Guti
 

Doom: DJGPP vs Watcom vs. Digital Mars vs. CC386

Somewhere I read (maybe urban legend) that authors of Doom tried to recompile it with DJGPP and wondered how faster does it run so decided to use DJGPP for the next game - Quake...

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DOS gives me freedom to unlimited HW access.

RayeR

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CZ,
15.01.2026, 08:04

@ Rugxulo
 

Doom: DJGPP vs Watcom vs. Digital Mars vs. CC386

On real DOS machine (Pentium Pro 200) the differences are not so fancy,
I got:
original doom: 64,08 FPS
djdoom: 66,65 FPS
others crashed/hanged

BTW for really old PCs it's interesting to try DOOM8088 (VGA/EGA/CGA/MDA/textmode) https://github.com/FrenkelS/Doom8088

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DOS gives me freedom to unlimited HW access.

RayeR

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CZ,
18.01.2026, 16:07

@ RayeR
 

Doom: DJGPP vs Watcom vs. Digital Mars vs. CC386

And on old 486DLC @40MHz
original doom: 11.700 FPS
djdoom: 12.414 FPS
Doom8088/386/VGA-hi: 20.724 FPS

---
DOS gives me freedom to unlimited HW access.

Rugxulo

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Usono,
18.01.2026, 16:46

@ RayeR
 

Doom: DJGPP vs Watcom vs. Digital Mars vs. CC386

> And on old 486DLC @40MHz
> original doom: 11.700 FPS
> djdoom: 12.414 FPS
> Doom8088/386/VGA-hi: 20.724 FPS

IIRC, GCC never did anything for 486 besides adding extra alignment to the 386 output (since 486s were very sensitive).

Realistically, what else could be done for 486? Supposedly they preferred more RISC-y code (unlike 386 that preferred densely packed CISC instructions) due to pipelining. Maybe also avoid AGI (address generation interlock?), not sure.

Granted, the 486 was twice as fast as the 386 at the same clock speed, so there's clearly room for optimizations. But I guess just conflating it as a faster 386 is easier.

However, for comparison, I think GCC had much better support for Pentium 4.

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