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386 cpu and Doom

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First post, by 386SX

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Hi,
lately trying the GBA handheld version of Doom I was thinking about how "well" the ARM7 16Mhz custom cpu actually get to run Doom on this console, but also the SNES version (ok with the help of the SuperFX2 20Mhz on-cartridge-chip if I remember).
I 've read somwhere they were probably both lighter/optimized version of the Jaguar port of the engine so I was thinking, did anyone built a lighter port of the engine for the x86 version 386-oriented?
Thank

Reply 2 of 25, by 386SX

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CelGen wrote:

I know for a fact that the regular version of DOOM will run on a 386.

Sure it runs but it seems that even with the fastest cpu/vga it will still be slow. Mine 386DX-40 with 256kbyte L2,Ati 28800-5 and fastest ram I found (16mb 60ns) still runs obviously slow and things will not change much with faster vga I imagine. For this I was thinking about lighter engine of the game.

Reply 3 of 25, by Scali

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A 386 just isn't that fast. Other than that it's not really different from a 486 though. DOOM is optimized for 386/486 CPUs.
On a 386 you can set the 'lowres' mode, and make the window smaller.
I've played it even on a 386SX-16 back in the day. The slowest 32-bit x86 ever. It wasn't fast, but it ran.
On a 386DX-33 or 40 it is quite playable at reasonable window size.

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Reply 4 of 25, by 386SX

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Scali wrote:
A 386 just isn't that fast. Other than that it's not really different from a 486 though. DOOM is optimized for 386/486 CPUs. On […]
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A 386 just isn't that fast. Other than that it's not really different from a 486 though. DOOM is optimized for 386/486 CPUs.
On a 386 you can set the 'lowres' mode, and make the window smaller.
I've played it even on a 386SX-16 back in the day. The slowest 32-bit x86 ever. It wasn't fast, but it ran.
On a 386DX-33 or 40 it is quite playable at reasonable window size.

Sure but I imagine it was more a 486 oriented game that a 386 one cause even with the fastest options I can't say it's smooth. The mroe difficulty you set the slower it will be. Even in the GBA or SNES version it's still obviously far from the smoothness but I'd bet a 386 at 40Mhz could do more with some less detail in "geometry" and ligthning.

Reply 5 of 25, by Scali

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Well, less detail in geometry is simple: Take a level editor and make your own simplified levels.
Lighting, I doubt it. Doom uses precalced lighting in the textures, I don't think you'll gain much by removing that.
The SNES version seems to have removed the textures from ceilings and floors, that saves quite a bit of CPU-work.

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Reply 6 of 25, by jesolo

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As I recall, the minimum requirements for Doom is a 386 CPU with 4MB of RAM, but this is suboptimal and you are not going to get an enjoyable experience out of the game.
As a matter of fact, even on my old Cyrix 486 DLC-40, Doom's performance did suffer in large maps with lots of monsters.
A 486DX2-66 or faster is recommended if you want to play with "high" resolution (the F5 key as I recall toggled it) and full screen.

Reply 7 of 25, by dogchainx

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I had a 386DX-40Mhz when that came out. It was playable, but wasn't super-smooth until I got my 486DX2-66. Even then, an upgrade to my pentium 90 (100MHz overclocked) made it even better and that is the computer I used for Doom over modem play.

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Reply 10 of 25, by FaSMaN

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My Cyrix Cx486DLC-40 , has doom playable on lowres-mode (smooth) it can do highres but its not too great , this is with a Cyrus Logic 5xxx VGA card, from my understanding the doom source code is extremely well optimized so I doubt we will be able to get it to play any better.

The GBA is a much lower resolution and the game does run in lowres and I am pretty sure they did a lot of optimization for it to make it playable.

Reply 11 of 25, by Scali

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noshutdown wrote:

i got 2fps on a cyrix486dx-25, guess the fastest amd386dx-40 wouldn't be much faster than that. even amd486dx5-133 scored only 8fps.

Well, then there must be something wrong.
A 486DX2-66 with a good VLB card will play Doom quite smoothly, somewhere between 35-70 fps in most places.
Are you sure you're not confusing Doom with Quake?

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Reply 12 of 25, by Scali

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Rawit wrote:

SNES Doom isn't using the Doom engine. It uses an engine written by Randy Linden, creator of Bleem! I'm not sure of the GameBoy version uses the same engine as the SNES one.

The Doom engine is very specifically tailored to mode X VGA and x86 CPUs.
You'll need a different engine for every other platform. That engine would still use the same basic principles though: raycasting a 2.5d map, and drawing scaled vertical texturemapped columns (perhaps the SNES has some hardware trickery to draw those columns more efficiently).
The ceiling/floor are more complicated, and use some precalced tables on x86. On SNES they apparently just left them out altogether, making it more of a Wolf3D-like engine with slightly more complex level design.

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Reply 13 of 25, by dondiego

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On my 486 dx 33 with octek hippo vl+ and cirrus logic cl-gd5428 vlb Doom runs well, i get 16 fps with default screen size and 11 fps with an isa trident 9000i. However Doom 2 runs slower and i need to switch to low detail mode.

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Reply 14 of 25, by 386SX

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I've tried for the first time the TX486DLC-40 on my motherboard and man it's faster even if you'd expect even better from a 486. By the way it's impressive, Doom is playable almost smooth at lowres-no-borders. 3Dbench 1.0 jumped from 14,9fps (full dos autoexec/config) to [[[ 20fps ]]] with the same ATi 28800-5 1MB, The motherboard ETEQ based support the internal Cyrix cache so it's basically another story.
But it's not a 386 so I switched back. 😁

Reply 15 of 25, by Artex

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I remember being so pissed because my parents got a shiny new 386 SX-16 back in 1991 (AWESOME!) but only came with 2MB RAM so it couldn't run DOOM (Heartbreak). It could run Stunts though, so I played the hell outta that - and Jill of the Jungle. 😀

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Reply 16 of 25, by feipoa

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I get 14.1 fps with timedemo3 using a 486SXL-40 and a CL-GD5434 graphics card, which is pushing PGA-132 boards to the limit.

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Reply 17 of 25, by FGB

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feipoa wrote:

I get 14.1 fps with timedemo3 using a 486SXL-40 and a CL-GD5434 graphics card, which is pushing PGA-132 boards to the limit.

I don't believe 14.1 fps is possible with a TX486SXL-40. Unless you reduce screen size. Typically these overdrives get stuck at ~13.<5 fps, no matter what BIOS settings ( 0 WS, slow refresh at max) or GFX or BUS (ISA or VLB) one uses.

P.S: No offend.. I just can't believe it because I tested around with these overdrives sooo much and never ever reached 14.x fps. But well.. I don't say it is impossible. I thought for years a AMD 5x86 running at 4x33MHz would never ever get beyond the 83.3fps barrier at 3DBench 1.0 but than I got a motherboard that seems faster in this category than any other board around and BOOM... the score went through the 90fps roof...

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Reply 18 of 25, by feipoa

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What was your L1 enabling strategy? What chipsets and graphic cards did you try?

Actually, I can get up to 14.99 fps if I use 0 ws. I am using the fastest PGA-132 board encountered - an AMI Mark V Baby Screamer based on the VLSI 330/331/332 chipset. This board has better DOOM scores, for example, than a SiS Rabbit (SiS 310/320/330), UMC 481/482, or PEAK/DM (Chips 351/355/356). I am also ensuring that L1 is properly enabled. The ISA bus is run at 10 MHz, which is the only option when a 40 Mhz CPU is installed in this board. It runs at 8 MHz with a 66 MHz osc. though.

As for the screen size, I am using whatever the default screen size is for the Doom demo benchmark. I think it is v1.9.

Click for larger, more readable view to see this board in action with different graphic cards. The GPUs make a big difference.

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Reply 19 of 25, by FGB

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Thanks!
I used the tool from the "Make it 486" floppy which came with various SXL / SLC CPUs unless the board had native support. I used default settings so there might be some headroom.
But I have to admit I never has the VLSI / Intel licensed board. Still have to bench my Acer based board. It seems quite fast.

See my chart for comparison:

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