486 DX2-66 should really be considered minimum requirements for Doom or Doom 2.

For Doom running in high detail, full screen, and relatively smooth frame rate (35 FPS), you'll probably want at least a 486 DX4-100 or Pentium 75 as a minimum.

For Doom 2, I'd go with a Pentium 100 or better. Especially for higher difficulties where there can be loads of enemies on the screen.

Having a decent VLB or PCI video card and adding L2 cache on the motherboard helps as well.

If you don't mind source ports, nowadays, there is FastDOOM which has excellent performance optimizations and some crazy video modes to try.

Gmlb256 wrote on 2023-11-13, 23:53:

If you don't mind source ports, nowadays, there is FastDOOM which has excellent performance optimizations and some crazy video modes to try.

This is completely not retrocomputing, but there's also a recent official port of Doom (and I think Doom 2) by Bethesda to modern Windows systems on Steam. It's not remastered in the sense that the graphics certainly look original, but it will run on Windows 10 happily... and at probably an artificial speed designed to mimic what someone at Bethesda thinks is the 'right' speed for it.

SETBLASTER wrote on 2023-11-13, 23:30:

as i kid i also remember with my first pentium 133mhz how fas things were running like Doom and i didn't like how fast it was .

You're probably misremembering.

Doom 1&2 are capped at 35 FPS. Even if you were to play these games on a 1 GHz Pentium 3, they wouldn't run any faster than that during normal gameplay.

SETBLASTER wrote on 2023-11-13, 23:30:

as a kid i spent hours on Doom and Doom 2 using a 486 dx2 cyrix 66mhz. […]
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as a kid i spent hours on Doom and Doom 2 using a 486 dx2 cyrix 66mhz.

some years ago i rebuilt that very same machine. Only to find out that doom and doom2 were super slow. Maybe it was because as a young kid i thought that was the way it should run and never detected that problem?

as i kid i also remember with my first pentium 133mhz how fas things were running like Doom and i didn't like how fast it was .

what system specs are the minimum to enjoy DooM and doom2 ? is there a 486 processor that can handle it? or an overdrive processor? so far i kbow it works very nice with an amd 133mhz

486DX2/66 shouldn't have any issues running Doom. Most people had machines like that when the game was released.

The question here is: what's your video card? If you used an ISA card rather than VLB or PCI, chances are that's your bottleneck, not the CPU.

Also the Cyrix 486 is probably slower clock for clock than the Intel, although I don't know that for sure.

I first played Doom on a 386SX16 which is probably below minimum. Fast VGA access is a need, so ET3000/4000 is probably a good minimum on that, as well as a 386DX.

Doom 2 though that's definitely 486DX. Things are more hordey. If your 486DX is running either Doom slowly, you're bottlenecking on video.

I first played DooM on a NES.
Which is defiantly well below the minimum spec for DooM and a PC come to that!

But to answer the OP.

What WAD are you wanting to play?
Some of those custom WAD and iWAD files can require a lot lot more than these guys would have you believe so far.

I just tried to play Holy Hell on a P4 3.06 with a Geforce 6200 and it didnt like that at all it didnt.

keenmaster486 wrote on 2023-11-14, 01:31:

486DX2/66 shouldn't have any issues running Doom.

It won't run Doom at full speed (35 FPS) with full screen + high detail + lots of enemies. Doom 2 tends to be even worse as it features larger open areas with lots more enemies.

Doom was one of those games that arguably was designed for specs beyond what was available at the time of release.

Joseph_Joestar wrote on 2023-11-14, 01:10:

SETBLASTER wrote on 2023-11-13, 23:30:

as i kid i also remember with my first pentium 133mhz how fas things were running like Doom and i didn't like how fast it was .

You're probably misremembering.

Doom 1&2 are capped at 35 FPS. Even if you were to play these games on a 1 GHz Pentium 3, they wouldn't run any faster than that during normal gameplay.

It might be the smoothness of the gameplay they are referring to. If one is used to the more stuttery sub-35 frame rates, then running at a consistent 35 FPS might feel too smooth.

ElectroSoldier wrote on 2023-11-14, 02:18:

I first played DooM on a NES. Which is defiantly well below the minimum spec for DooM and a PC come to that! […]
Show full quote

I first played DooM on a NES.
Which is defiantly well below the minimum spec for DooM and a PC come to that!

But to answer the OP.

What WAD are you wanting to play?
Some of those custom WAD and iWAD files can require a lot lot more than these guys would have you believe so far.

I just tried to play Holy Hell on a P4 3.06 with a Geforce 6200 and it didnt like that at all it didnt.

Doom was never on the nes, just the snes and it required extra hardware in the cartridge.

Don't even bother playing Doom 2 Downtown with anything less than DX4-100.

DosFreak wrote on 2023-11-14, 02:46:

ElectroSoldier wrote on 2023-11-14, 02:18:

I first played DooM on a NES. Which is defiantly well below the minimum spec for DooM and a PC come to that! […]
Show full quote

I first played DooM on a NES.
Which is defiantly well below the minimum spec for DooM and a PC come to that!

But to answer the OP.

What WAD are you wanting to play?
Some of those custom WAD and iWAD files can require a lot lot more than these guys would have you believe so far.

I just tried to play Holy Hell on a P4 3.06 with a Geforce 6200 and it didnt like that at all it didnt.

Doom was never on the nes, just the snes and it required extra hardware in the cartridge.

Been so long since I played it... Ill take your word for it.

Shponglefan wrote on 2023-11-14, 02:39:

keenmaster486 wrote on 2023-11-14, 01:31:

486DX2/66 shouldn't have any issues running Doom.

Doom was one of those games that arguably was designed for specs beyond what was available at the time of release.

Yup, or at least beyond what most people had. It was still in the era where reducing the screen size smaller than fullscreen was a thing. A 486DX2/66 is the system I wished I had to run Doom back then. The first time I saw Doom running on a half-decent system I was amazed at how smooth that wavy titlescreen wipe effect was. 😳

Joseph_Joestar wrote on 2023-11-14, 01:10:

SETBLASTER wrote on 2023-11-13, 23:30:

as i kid i also remember with my first pentium 133mhz how fas things were running like Doom and i didn't like how fast it was .

You're probably misremembering.

Doom 1&2 are capped at 35 FPS. Even if you were to play these games on a 1 GHz Pentium 3, they wouldn't run any faster than that during normal gameplay.

I got good memory!, imagine the speed i was playing with a dx2 66mhz that when i tried with a pentium it felt super fast maybe near 35FPS

Gmlb256 wrote on 2023-11-13, 23:53:

Having a decent VLB or PCI video card and adding L2 cache on the motherboard helps as well.

If you don't mind source ports, nowadays, there is FastDOOM which has excellent performance optimizations and some crazy video modes to try.

true, i saw videos about fastdoom and those were amazing, but i was giving an example, because i bet there are many other games from that era where a dx2 66mhz is not enough

keenmaster486 wrote on 2023-11-14, 01:31:

486DX2/66 shouldn't have any issues running Doom. Most people had machines like that when the game was released.

The question here is: what's your video card? If you used an ISA card rather than VLB or PCI, chances are that's your bottleneck, not the CPU.

Also the Cyrix 486 is probably slower clock for clock than the Intel, although I don't know that for sure.

sadly i can´t remember that one. because i know i had 2 cards. i bought a trident VLB some time during windows 3.1 and i can´t remember what card i had before that.
but hard to remember if i was playing before the vlb card or after.

What happens if you don´t have a VLB slot in the motherboard? you are stuck to play Doom at terrible speed even if you put a 486 overdrive 100mhz? or is there an ISA 16bit card that can match a vlb?

ubiq wrote on 2023-11-14, 03:17:

Yup, or at least beyond what most people had. It was still in the era where reducing the screen size smaller than fullscreen was a thing. A 486DX2/66 is the system I wished I had to run Doom back then. The first time I saw Doom running on a half-decent system I was amazed at how smooth that wavy titlescreen wipe effect was. 😳

back then it felt perfect for me, and i loved it, perhaps i reduced the screensize a bit, and i had that custom wad for alien doom and i loved that one too. When i jumped to a pentium 133MHZ in 1996 , it was a time i did not play doom nor doom2 anymore as it was more of a time of duke nukem 3d , diablo, red alert, . but i did try doom on that new PC and it felt super fast.

I used to play Doom and Doom 2 on a 486 dx2 66 for many years, ran great, no problems. If it’s not running well on that processor, I’d look at some other part of the system like the video card, motherboard, ram, etc. Of course that’s stock Doom and Doom 2 with the stock wads. Only had to upgrade for quake. A 486 dx2 66 is fine for Doom.

Are you playing on windows maybe instead of rebooting into dos? Or running other stuff in the background? I still suspect some other component like the video card or mother board etc

Fast ISA for Doom are the later chipsets you can find on ISA like GD5434, I favor those. Also ET4000 and I think Ark1000PV are findable on ISA. There's also an Oak chipset that's quite fast and some later versions of the Tridents.

But in general yeah, make sure your L2 cache is working and you are not deturboed, 4MB is a bit tight, 8MB is smoother, but I don't think there's a point in going beyond 16 at all.

Settings in CMOS setup, see how much you can tighten cache and RAM timings 3-1-1-1 is about average and should be fairly good, 3-2-2-2 will feel sluggish in comparison and you might only need that if you've got 25ns cache and 70ns RAM. 15ns and 60ns and you can try for tightest 2-1-1-1s .... but you might need to slacken it off if you bump the bus to 40 later and run dx2/80

I think we are nowadays used to much higher refresh rates. Also, DOOM used v sync so your frame rate drops quite a bit when you don’t make it to 35 (next value is 23.3). No 486 dx2 66 can keep up with 35 fps during the game, so it can be quite a different experience then the current 120+ Hz modern game setups.
By the way, my Cyrix Dx2/66 runs Phils benchmark (fullscreen no hud no sound) with 23 fps and that was a budget system (but with VLB). At 80 MHz it does 29 fps. That might still feel “slow” depending on what you expect.

SETBLASTER wrote on 2023-11-14, 04:21:

What happens if you don´t have a VLB slot in the motherboard? you are stuck to play Doom at terrible speed even if you put a 486 overdrive 100mhz? or is there an ISA 16bit card that can match a vlb?

Doom does 8 bit writes directly to VGA ram, whats worse it does 8bit reads too. That might have been optimal in a narrow timeframe around late 1992, but by the time Doom 2 was being released this was becoming a very bad practice. 1994 Heretic didnt inherit Dooms mode Y renderer and does much better on fast graphic cards while Doom1/2 is heavily bottlenecked by the granular writes and video reads.

Overclocking ISA bus is a good substitute for VLB.