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486DX2/VLB build

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First post, by jheronimus

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Hi, all

I decided to make a "classic" 486 build to use for MT-32 games. I've used a Chaintech 4SLP motherboard from my failed 5x86 build. No matter how hard I tried, this board always gave me issues with both 5x86 and AMD DX4-100 (even though it explicitly supports the latter). However, with a regular 486DX2-66 the experience was extremely smooth and worked the first time I tried to boot it.

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The board has 256KB L2 cache and a SIS471 chipset. The battery was replaced by the previous owner and it seems to have some sort of an aftermarket VRM module installed. I fitted the motherboard with 4x4MB of RAM — I could never fit more than 16MB of memory in this board anyhow.

I'm actually using Overdrive DX20DPR66 v4.0 even though I have a regular 486DX2 — just wanted to use the stock heatsink. Both chips have write-through cache as far as I can tell and according to CHKCPU.

I'm using a VLB Cirrus Logic CL-GD5428 board upgraded to 1MB of VRAM and a VLB controller with a UMC chip. Connected to it is a 1.6GB Samsung hard drive — the largest one I have that still has the "old disk whirring" sound. Also, I have a 24x CD-ROM connected — the slowest one I have that still supports CD-R/CD-RW.

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For sound I'm using a Vibra CT2940 with true OPL3. I also have a CT2230, but I'm using it in an AMD K6-3+ build that is better suited for General MIDI games.

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Finally, I'm using a 3COM 3C509 card for NIC. Roland MT-32 is connected to Sound Blaster and I'm using SoftMPU. So far, only Legend Entertainment games give me troubles. Eric the Unready reverts to Sound Blaster, and music in Superhero League of Hoboken freezes at intro scene (but I can skip it and get music in main game).

Turbo works really well — I can use the case button and Ctrl + Alt + +/- even while running the system. I'm still experimenting with options, though, and will post my benchmarks later and share my experience with games like Wing Commander 1/Ultima 7. If I can't get them to work then I'll downgrade to 486SX-30 or UMC U5S-SUPER33. I don't have a DX-30, unfortunately, but I can probably try to downclock my DX2 to DX2-50 and see if I get anything useful with Turbo.

Overall, compared to 5x86/DX4 this build seems almost trouble-free, but I don't really know why. I mean, DX2, DX4/100 and 5x86 all use the same 33MHz FSB speed, so it can't really be speed issues.

I'll post the photos of the final build later, but for now I have some questions:

1) I have a Yamaha SW60XG that would be nice to use in this build. It can be set to use 300h address — since my SB16 (and consequently, MT-32) is using 330h. However, I'm not sure if I can daisy-chain them together. How do I go about this? MT-32 goes into line-in of SW60XG, SW60XG goes into line-in of SB16 or what?
2) I have atrocious performance in Duke Nukem 3D. Not the most important game for this build, but still — I've seen people on YouTube play DN3 on 486DX2 in 320x200 with no issues. I've tried running UniVBE 6.7 from Vogonsdrivers.com and from Phil's benchmark pack, but in both cases it says that my card is not supported — even though 5428 is explicitly listed as supported in Readme. Am I doing anything wrong or should I use some different version of UniVBE?

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Reply 1 of 16, by clueless1

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Good looking system! I suspect once you test the turbo switch you'll find it allows Ultima 7 to play at a good speed. WC1 should do fine with setmul disabling L1 (or do it manually in BIOS).

Regarding DN3D -- I have not tried it on my DX2-66, but based on my experience with Doom, I would expect DN3D to be sluggish. Doom benchmark for me is about 24-25 fps, with slow spots getting down to about 15 fps. And my gut tells me DN3D in 320x200 is more demanding than Doom. You can turn on the framerate indicator in Duke by typing 'DNRATE' in-game. Run around and see what it's showing. Oh, and if I remember correctly, you can gain some speed by turning some audio settings down in Duke's setup.exe Reduce audio channels, sound quality, etc. It should make a bigger difference on a slower system like a 486.

Someone correct me if I'm wrong, but I don't think Univbe will help performance in 320x200. It's mainly for SVGA. Still, you can try older versions (Sci Tech Display Doctor 5.3a and 6.53) to see if they support your VGA card. I have a Genoa-branded Cirrus Logic VLB, and I do get support on with SDD5.3a. Wouldn't hurt to try.

The more I learn, the more I realize how much I don't know.
OPL3 FM vs. Roland MT-32 vs. General MIDI DOS Game Comparison
Let's benchmark our systems with cache disabled
DOS PCI Graphics Card Benchmarks

Reply 2 of 16, by jheronimus

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Yeah, as it is, Duke Nukem 3D gives me single digit FPS in open areas of the first level and 12-19FPS in buildings. I can certainly see myself thoroughly enjoying the game this way 20 years ago, but I definitely have no reason to do that now 😀

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Reply 3 of 16, by badmojo

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A DX2 66 should handle VGA Duke3D OK - but not SVGA obviously. Sounds like something's not right - have you fiddled with the BIOS for that motherboard? Caches all enabled? What's with that EPROM? The sticker appears to be missing, I can see the little window.

Do you have another VLB VGA card you can try? I'd use Phil's benchmark spreadsheet and tools to determine if your machine is performing on par with similar systems.

Life? Don't talk to me about life.

Reply 4 of 16, by chinny22

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it's sad you couldn't get the faster CPU's working, but VLB was tricky to get working best of times, and THINK I remember DX4 and later moreso.
For me DX2 66 is the ultimate CPU to pair with VLB, Its also the "true" 486 being the minimum requirements system for years.
DX4 and later suit PCI 486's, or "Ultimate" 486.

Re Duke3d. I played though the 1st episode on my DX2/66 with ATI Mach 64 VLB and for the most part was ok, not smooth but ok.
Playing on the EXACT same PC recently, HDD and all, it feels unplayable, Maybe the Atomic edition doesn't run as earlier versions but I think the more likely reason is my standards have become higher!

Reply 5 of 16, by jheronimus

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badmojo wrote:

Do you have another VLB VGA card you can try? I'd use Phil's benchmark spreadsheet and tools to determine if your machine is performing on par with similar systems.

Only a non-upgradable 512KB CL-GD5428. I'll try it just to rule out the faulty card possibility

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Reply 6 of 16, by jheronimus

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Time for some benchmarks:

Normal mode:
3DBench: 44.4
Chris's 3D Bench (SVGA): 14.5/8,7FPS
System Information 8: 143.3
Speedsys: 24.99
Doom timedemo: 24,7FPS

Turbo:
3DBench: 18.7
Chris's 3D Bench (SVGA): 5.3/3.1FPS
System Information 8: 51.9
Speedsys: 15.06
Doom timedemo: 9,36FPS

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Reply 7 of 16, by shamino

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Duke Nukem 3D is the game that finally convinced me I needed a better video card back then. We had upgraded from the DX2/66 to a Cyrix 6x86 133MHz system, but the video card was still an ISA Cirrus Logic CL-GD5426 1MB. DN3D was so choppy that I knew something had to be wrong, and that it had to be the graphics card. After upgrading to an S3 Virge PCI, it was dramatically improved. This was in standard 320x200 mode, I think SVGA was not fast enough to be enjoyable.
However, since your Cirrus card is VLB, I'm not sure if it would be suffering from the same issue.

Reply 8 of 16, by clueless1

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With the exception of Chris' 3D VGA, very similar to my DX2/66 results.

Normal (yours/mine):
3dbench: 44.4/43.4
Chris 320: 14.5/26.7
Chris 640: 8.7/8.2
Sysinfo 8: 143.3/131.9
Speedsys: 24.99/25.14
Doom: 24.7/24.3

Turbo (yours/mine):
3dbench: 18.7/17.5
Chris 320: 5.3/10.7
Chris 640: 3.1/3.0
Sysinfo 8: 51.9/43.7
Speedsys: 15.06/14.95
Doom: 9.36/9.02

That is strange how low your Chris 320 scores are. Everything else pretty much lines up. I'm going to copy Duke3D on here and test it and get back.

The more I learn, the more I realize how much I don't know.
OPL3 FM vs. Roland MT-32 vs. General MIDI DOS Game Comparison
Let's benchmark our systems with cache disabled
DOS PCI Graphics Card Benchmarks

Reply 9 of 16, by jheronimus

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clueless1 wrote:

With the exception of Chris' 3D VGA, very similar to my DX2/66 results.

I posted only SVGA results for Chris'. It's just that it produces a score and an FPS count, hence two numbers.

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Reply 10 of 16, by jheronimus

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I tried running Duke Nukem 3D with all sound devices disabled. Now I get around 15FPS in open areas and up to 25FPS in rooms.

The weird thing is, low FPS in this game really feels different than it would in a modern game, for some reason. I mean, 15FPS should be unplayable, but here it's just choppy at times.

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Reply 11 of 16, by clueless1

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Starting a new game, I'm at 11 fps just standing there in the initial position. The open areas are between 9-11 fps. The enclosed areas seem to be between 10-17 fps. This is with SB Pro2 and GM music enabled.

edit: with sound and music disabled, I get 14 fps standing at the starting point. Open areas around 13-19 fps and enclosed areas around 13-24 fps.

The more I learn, the more I realize how much I don't know.
OPL3 FM vs. Roland MT-32 vs. General MIDI DOS Game Comparison
Let's benchmark our systems with cache disabled
DOS PCI Graphics Card Benchmarks

Reply 12 of 16, by badmojo

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Wow I'm surprised how slow it is in the cold light of day - I played countless hours of Duke3D on my trusty DX2 66 and loved it. It's all relative I guess.

Thinking about it though I wouldn't even play DOOM on a 66MHz 486 these days, I use a P166MMX, and Duke3D is 3 years younger than DOOM.

Life? Don't talk to me about life.

Reply 14 of 16, by Private_Ops

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That chip to the right of the power connector with the "window". I'm not terribly knowledgeable with those types of chips but, I'd cover that window with a small piece of black tape.

Reply 15 of 16, by amadeus777999

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Nice system!
Your speeds seem "within the margins". It can be quite sobering to see some games running on original hardware only to burst an "ancient bubble".

Reply 16 of 16, by alexsydneynsw

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Duke 3D was released in 1996 (same year as Quake), and 486 DX2 was released in 1992 - the year when Wolfenstein 3D just came out.