Authentic:

1) Socket 7 ATX board, Intel 430TX should be easiest to get
2) Pentium MMX 200-233 or AMD K6-2 300-400
3) 64Mb RAM
4) S3 Virge or similar cheap and abundant 2D video card. Maybe Matrox Mystique/Millenium/Millenium 2, if you want good analog signal quality at the cost of compatibility
5) Some popular and abundant ISA sound card like Yamaha 718/719

Not-so authentic:

1) Late Socket 370/Slot 1 board with VIA CPU support and ISA slot(s).
2) VIA C3 Nenemiah, but Pentium II or early Pentium III are also serviceable with ACPI throttling, to cover variety of DOS speed requirements
3) 64-512 Mb RAM
4) Any decent AGP card with VESA 2.0/3.0 support, like Riva TNT2
5) ISA sound

HDDs, optical drives, General MIDI, etc are mostly irrelevant or optional.

Those specs are way more than I want. I want the following:
* 486DX4 or Pentium
* 16-32KB RAM
* Hard drive between 350 and 500MB
* EVGA or SVGA graphics
* Sound card at least bSB16 or true compatible
* Standard ports
* CD drive at least 4x
* Software preferred but not necessary: I can install it myself. I can even partition and format the HDD myself.

Search "486 computer" on eBay and find one you can either use as-is or use parts from it - plus the case. The AT case is actually the hardest part to find these days.

You can source the other parts on eBay as well. Locally, recycle centers sometimes have what you're looking for, depending on where you're located.

I assume you mean MB, not KB on your RAM spec. 16-32MB is appropriate for a 486, less useful the further into the Pentium era you get, running Win9x etc.

Why the specific limitation on hard drive size? You can find those too, but be careful on shipping. Compact Flash cards of varying sizes (industrial cards <1GB and consumer cards >1GB) are popular because they have no moving parts and are pin-compatible with IDE. If you're experimenting with file compression though, you may want the limited speed of a spinning disk to keep you accountable in your code.

For SB16 cards I'd recommend looking for the jumpered type such as CT1740, CT1750, etc., rather than the Plug-N-Play types. PnP cards work fine and you may prefer them, but they are less fun. If you get PnP, use the UNISOUND utility to initialize them for convenience. Check this page for the model numbers: Sound Blaster: From best to worst

Standard ports on a 486 may or may not need to be added with expansion cards (usually Multi I/O cards with HDD/FDD, serial, and parallel). Some motherboards will have them built in, but will need breakout cables.

There is no such thing as "EVGA". What you want is a nice 2D SVGA card. S3 and Cirrus Logic won't do you wrong.

For 486 motherboards you have three options for your bus: ISA only, VLB, and PCI. ISA only is the worst for a 486 class system. VLB and PCI are what you want, but PCI is easier to work with. You will have to make sure your video card matches your bus.

For CD, any generic IDE CD-ROM drive will work.

You will find an Ethernet card and the MTCP software suite invaluable for transferring files once you have the OS loaded. The 3C509 series of cards are plentiful, inexpensive, performant, and reliable.

Can't recommend any 486 for daily use. From practical point, 486 systems are stuck in limbo: too fast for early DOS stuff, but too slow for late DOS. They are "fun" to mess with, if you're more hardware tinkering oriented, but not software.

Harry Potter wrote on 2023-06-29, 14:42:

Those specs are way more than I want. I want the following:
* 486DX4 or Pentium

Why? These will be insufficient for late DOS, but already too fast for older DOS games without slowdown features

* 16-32KB RAM

I hope you mean 16-32MB...

[...]

* EVGA or SVGA graphics

EVGA is a graphics card brand which is probably not what you mean here. What is "EVGA"?

* Sound card at least bSB16 or true compatible

Huge rabbit hole to go down here. I like C-Media CMI8330 cards for single-card use, but you can go for Creative cards if you have money to spare and don't mind the DMA and MIDI bugs

I'm sorry. The first PC I got was labeled as having an EVGA adapter. It seems to be an SVGA adapter with only 256 colors. Also, thank you for correcting my error: I did mean MB.

Harry Potter wrote on 2023-06-29, 14:42:

Those specs are way more than I want. I want the following:
* 486DX4 or Pentium

I'd go with a Pentium instead of a 486. You can always throttle a Pentium's speed down to 486 levels, but you can't speed up a 486 to a Pentium's performance.

Insofar as finding one, your best bet is likely going to be Ebay or local ads (Craigslist, Facebook Marketplace, etc.).

You can set up a search alert on Ebay for something like "Pentium computer" and it will alert you of any new ads for such machines. Then it's just a matter of being patient until something shows up for sale.

Well, from my experience there is no one perfect DOS machine. Which machine to choose is actually a function of what software you're going to use on it.

I would either use DosBox-x/86box, P200 on Socket 7 or PII Klamath 233-266 on 440LX. As noted by other posters, a 486 is not good enough at anything.

Well, its main purposes are games, programming and fun. I also want to run emulators and file compression on it. I want Windows 3.1 and work applications on it, such as word processors and databases, but can supply those.

Harry Potter wrote on 2023-06-29, 17:58:

Well, its main purposes are games, programming and fun. I also want to run emulators and file compression on it. I want Windows 3.1 and work applications on it, such as word processors and databases, but can supply those.

Whoa, Windows 3.1 and work applications is a whole different can of worms 😮

Why? Because work applications want higher resolutions than 640x480, preferably at more than 16 colours, so video card gets more relevant - and Windows 3.1 isn't anywhere near as flexible as later Windows versions (each resolution/refresh rate requires a separate driver) and Windows desktop acceleration performance is very different to DOS framebuffer performance.

I ran Win 3.1 until 1999 on a Pentium 60, which ran it extremely smoothly, using an S3 868 1MB card, which was a bad choice - with 1MB it only managed 800x600@16b colour, and did so at 60Hz. Also the analog circuitry was so bad even on my low-end 14" monitor at the time it was visible that image wasn't as sharp as it should be.

What would I recommend in this case:
- at least 2MB video memory, with 4MB being better.
- where VRAM is slower than DRAM in DOS, it's faster in Windows.
- unless you have money to burn, that means VLB video cards are out (4MB cards are extremely rare and priced accordingly, even 2MB is an unusual premium) so you want PCI.
- be sure to go for something with good Windows 3.1 drivers (think ATi, Cirrus Logic, Matrox, S3 or Tseng - or indeed Weitek or Number 9)
- but you also want good DOS VESA support for the games, which means Ark, Cirrus Logic or S3 (or go for newer nVidia or 3dfx cards, or a Number 9 Imagine 128 if you can find one)
- be sure to go for a good brand with good analog circuitry.

The simplest choice (and probably cheapest due to wide availability) would be a good quality (Diamond, Elsa, Miro or Number Nine) S3 card, with chips like 868, 968, Trio or Virge. I particularly like the Virge/VX-based cards as they were premium back in the day with excellent build quality, but less liked now due to VRAM being a (pretty insignificant) bit slower in DOS. Look for say Diamond Stealth 3D 3000 or Elsa Winner 3000.

Thank you for all that info. 😀 How much would it cost to get one custom-built? I live in the U.S. BTW, I have to admit that I currently don't have the money for it but really want a DOS computer to replace a missing laptop. Of course, the only good things about that laptop were a 486DX4 microprocessor and 28MB RAM. Everything else sucked. 🙁

The best 486 is a Pentium. 🙂

486 and any CPU In general was great only till the newer and faster one appeared. When you have nothing to compare with it really helps to feel you have the greatest machine the money can buy.

And again, when considering building a DOS machine it is very important to fit it to the specific software you're going to use it with. And if you are planning to use a huge lot of DOS software, be prepared to buy a huge lot of different hardware cause there is no one perfect machine for every DOS program.

Harry Potter wrote on 2023-06-29, 19:02:

Thank you for all that info. 😀 How much would it cost to get one custom-built? I live in the U.S. BTW, I have to admit that I currently don't have the money for it but really want a DOS computer to replace a missing laptop. Of course, the only good things about that laptop were a 486DX4 microprocessor and 28MB RAM. Everything else sucked. 🙁

I'm located in the EU so can't really comment on US prices for such niche things. Some of the brands may be different where you are located (Elsa and Miro are German brands, probably less common over the pond). But if money is tight, you really want to do this yourself, as either a friend might help you for free (yay) or you will have to pay through the teeth for someone to do it non-charity.

Are you concerned about ability to put it together? In that case it might be worth looking for an early ATX system. That massively reduces the amount of unfamiliar hardware you have to deal with and lets you use modern cases and (with certain caveats) modern power supplies. You get PS/2 keyboard and mouse, which is not only a lot easier to find than AT DIN keyboards or serial mice, but there are also USB-PS/2 adapters galore (note that with modern peripherals they need to be active adapters).

For the same reason, Pentium is much easier than 486. You get PCI by default (yes, there are a few non-PCI Pentium boards, but no, you will not get them on a budget), they tend to have fewer jumpers and more BIOS settings to play with. I/O will be onboard rather than on add-in cards and basically the way to interact with the system will be the same as any pre-UEFI system; if you can use a P4, you can use a 1996-era Pentium system.

If you want simplicity (rather than ultimate tweaking options), go for an Intel OEM Pentium ATX board, like Thor, Marl, Tucson or Anchorage. They frequently have onboard VGA and audio which can be good. In particular, Thor and Tucson have S3 video and either Crystal or Yamaha audio with excellent SBPro2.0 and bug-free MIDI. No SB16, but they do do WSS (also 16b audio with higher sample rate) and if you really want SB16, you still have ISA slots to add one.

That's a lot! I like tweaks and, so, can handle settings, but, as I mentioned, my understanding of hardware is poor. 🙁 Are there any US-based web sites that sell custom systems?

Harry Potter wrote on 2023-06-29, 20:38:

That's a lot! I like tweaks and, so, can handle settings, but, as I mentioned, my understanding of hardware is poor. 🙁 Are there any US-based web sites that sell custom systems?

Just try a "me too" strategy - take a look at the others systems and build the same one for yourself.

If I could create a system, I would, but I'm not familiar with the hardware. 🙁

If you are not familiar with the hardware, why are you so certain about the very specific specs you want?

Start with the cheapest and easiest to source parts, which will get you a Socket 7 system that you can put any number of Pentium CPUs in, from 75 Mhz all the way up to 233. That will give you plenty of room to experiment and learn how this stuff works. You can do this on a $200 budget if you play your cards right.

If you want a pre-built system, I would recommend what I previously suggested: just save an Ebay search for "Pentium computer" and when a system gets advertised that is in-line with the specs you want, then buy it.

That's probably going to be the most straight-forward option. You can always tweak things later by swapping individual components.