I would first decide, on what architecture you would like to build your machine. With the 486 there are several possibilities:
- ISA - stone age
- ISA + VLB - the 486 classic
- ISA + custom local bus - if you adventurous
- ISA + PCI - the fast 486
- ISA + PCI + local bus - all in one, but implementations can be really bad
- EISA - ISA with added l33tness
- EISA + VLB - the ultimate classic
- MCA - the IBM way (PS/2)

If you don't want to spend a lot of time and money on hardware, you should choose between ISA + VLB and ISA + PCI. For a DX4 I would choose a PCI motherboard, since these CPU were introduced after the PCI bus was introduced. (VLB would be my choice for the DX2).

The next step is to choose the chipset. I choose the mainboards based on chipsets their are build around. The SiS 85C49x has good reputation (there are several revisions - the SIS496OR / SIS497OT pair is the latest). Also the UMC UM8881F + UM8886B and ALi M1489+M1487 are good. The Intel 420 chipsets are less common and there are mixed opinions about them (420ZX is ok, but 420EX is probably not so great). There is also OPTi, VIA and VLSI, but I don't have much experience with them.

Now you have to choose the motherboard manufacturer - almost everyone likes ASUS. And their PVI-486SP3 seems to be a good one:
-It does have ISA/VLB and PCI.
-The PCI is not bridged to VLB.
-Integrated HDD/FDD controller
-PS/2 mouse header.
-72-pin SIMM slots (though as far as I can remember EDO is not supported)

With the motherboard, CPU and RAM, it's time for a VGA. S3 seems to have great DOS games compatibility - a Vision/Trio64 or an early ViRGE would be my choice.

Sound cards - you can find a lot information on this forum about them - there's really no single configuration I could recommend. Except for adding a Gravis regardless whatever other Sound card you choose.

ISA + PCI sound like a good plan. I looked on eBay and the PVI-486SP3 motherboard is going for about $200 (with a DX4 processor, which I already have anyway)! I can't justify spending that much on ancient hardware. Any other suggestions for motherboard models?

I always recommend VLB for anyone who wants a good 486 system. Aside from Asus PVI-486SP3, PCI 486 boards are pretty much crap. Ideally what you'd want is a VL/EISA combo, but as these are hard to find, always use a DALLAS clock chip, and require EISA config files (which might be hard to locate), I would stick with ISA/VL board. There are tons of them, and they are cheap.

My two favourite types of VL boards are those based on the SiS chipsets, or the micronics boards common to the Gateway 2000 systems. Memory interleaving is a feature I wouldn't want to be without, so make sure your board supports it. Other things like support for writeback cache and 3V support are nice, but not as critical. However, if you want to use a DX/4 CPU, you'll need a separate voltage regulator if your board doesn't have one built in.

People in this forum seem to like graphics cards based on the S3 chipsets. If I were to go that route, I would probably get one based on the 805i, 864, 868, 964, 968 or TRIO64 chipset. S3 may be more compatible, but I strongly feel cards based on the Tseng ET4000/W32P chipset are a hell of a lot faster. The big problem with Tseng cards is quality. Most of them were value oriented and don't come with very good RAMDACs. Better quality boards are made by Hercules and STB.

For sound, I would prefer an SB Pro 2.0 with an LAPC-I card. MT32 cards are scarce and expensive though. Some people seem to like cards based on a certain version of the Crystal chipset that is SB Pro compatible and has a real OPL3 chip. What I'm running at the moment is an SB16 with a DBXG60 MPU-401 card. It's not a bad combo, but finding an SB16 without the hanging note bug is a real problem. DSP 4.05 seems to be the one to look for.

Hard drive performance is something that people on this site don't really seem to talk much about, but something I find critical for good performance. When possible, I always equip my systems with SCSI. The only problem is that on an ISA-VL board you don't really have a proper bus for a SCSI card. ISA is too old and doesn't provide enough bandwidth (though it's still useful for SCSI CD-ROM drives). VLB is a botched job and can't busmaster properly. The only decent SCSI cards on VL bus are the ones that have lots of cache, but these cares are few and far between. Therefore in your situation, EIDE may be the way to go. The basic EIDE VLB controllers really aren't too bad, but if possible grab a caching controller.

Just found this:

http://cgi.ebay.com/Worlds-Fastest-VLB-Mother … =item518ef234e6

Any good?

Nope, you found a real stinker. First of all, it's a Socket4 Pentium board. It doesn't support 486 CPUs as the seller stated. It appears to have VLB slots, which is a bad sign when PCI slots are also present. I would venture a guess that it is probably based on an OPTi chipset from what the seller said about not being able to find the right memory combinations for it. I have a similar board, and it's a real dog. Probably one of the worst Pentium boards ever made.

Let me have a look on ebay and see what I can dig up.

Wow. I searched eBay pretty well, and there's not much to choose from anymore. The best I could find it this:

http://cgi.ebay.com/ISA-486XV2-MOTHERBOARD-IN … =item1c0cd70501

It appears to the Asus 486SV2. It's probably a decent board. But, I doesn't natively support DX4s, and it looks like the cache installed is only 25ns, which is slow. That barrel battery will need replacing too.
I recommend just being patient and waiting for something good to pop up at a low price.

Here's an interesting one in the UK:

http://cgi.ebay.com/Old-Motherboard-486DX2-66 … =item414b3ae06d

rick12373 wrote:

I looked on eBay and the PVI-486SP3 motherboard is going for about $200 [...]

😳

I understand that the PVI-486SP3 has become one of the most expensive Socket3 mainboards recently, because it has the right features and is very well documented on the web (Half of it on VOGONS, I suppose 😉). But $200 still seems like a very overinflated price to me. Maybe you could get a cheaper one in a little while.

I sold a lot of 3 Asus PCI motherboards a month ago for $60. Around that time, I saw a few SP3s sold very cheaply.

I have been looking through my old stuff and found a socket 3 MB in there. It has 4 ISA slots and 4 PCI slots. It already has a CPU in it which is Am486 DX4-100 (an AMD chip I presume?). I tried looking for a model number or something so you could check it out for me but I couldn't see anything obvious. I tried taking some pictures but as you can see I was having trouble getting the Macro function of the camera to cooperate! I also found some socket 7 motherboards. They are for Pentiums aren't they?

It's a UMC UM8881 based mobo. Has everything you could want: PCI, onboard controller, 72 pin SIMMs. The only downside is the Dallas chip - if it lost its charge, you have to hack it to install a normal battery.

So what does that Dallas chip actually do?

Nice! You've got a Shuttle HOT-433 rev. 4.0.

If it works, it could be better than a PVI-486SP3 in some respects.

rick12373 wrote:

So what does that Dallas chip actually do?

It provides the real-time clock, CMOS memory and the battery to back these up, all sealed in one package. The problem with these is that when the battery goes dead, it is not easy to replace.

However I reckon the "unidentified" connector CN1 (refer to link above) is actually a connector to hook up an external battery.

The board even has pins for a PS/2 mouse connector cable, but I don't recognize the pin layout. If you don't already have the matching cable, you might have a hard time figuring out how to make one.

I have also found a PCI Diamond Stealth 3D 2000 4MB. Would this be a good choice for this board?

It's S3 ViRGE based, so it should be a good choice.

Anonymous Coward wrote:

Here's an interesting one in the UK:

http://cgi.ebay.com/Old-Motherboard-486DX2-66 … =item414b3ae06d

I believe it's a PC Chips board. I think it's very similar to this thing -

486 mobo with compact flash device and CD-ROM

The only recognisable difference between the two boards seems to be that the one featured on ebay has "normal looking" cache (as opposed to fake cache).

I don't think a DS128x7 can be powered by an external battery.

rick12373,

Dunno if this will help much, but here's my old 486DX100 that I used for years -> http://www.cmoo.com/snor/weeds/Weeds_486DX4-100.htm . Maybe something on that page will give you a few ideas, that old PC worked great for all of the old DOS stuff 😀

h-a-l-9000 wrote:

I don't think a DS128x7 can be powered by an external battery.

Ah right, the internal battery has to be disconnected for this to work.

I've found the manual for this board (see bottom of message). It doesn't mention the purpose of the CN1 connector, but it lists the pinout of the PS/2 mouse connector. 😀

Thanks guys. There's some really useful information there. I have a MB, video card and RAM. I think I have an ISA SB16 as well somewhere and maybe some AWE32's as well. What about getting a case to fit this stuff? I only have experience of the modern ATX cases and I am sure these would not work for an old board like this. What kind of case should I look for? Also, what are the hard drive considerations? I may have some old HD's around but is it possible to use a new IDE hard drive? I would not want an old hard drive to die and then lose my data. Actually the same goes for the CD drive does it matter if it is a newer one (obviously wouldn't be CDR or anything)? I have the same worry about the PSU. Would it be possible to use a new one? I suppose the connector to the MB would need to be adapted.

Sorry for being such a newbie! I am much more comfortable working on computers from the first Athlons to now.