
Currently, my oldest PC is a Pentium II, which I use Windows 98 on. So any DOS games I have are played on that. But I've been wanting a PC just a little older for a proper DOS setup. The problem there is that 486 era stuff has really went up in price over the years.
I'm still kicking myself. I had a once-in-a-lifetime side of the road score, something like 10 computers! They were mostly 486, maybe some were 386 or Pentium, I can't remember. All of the CPUs and RAM were pulled IIRC, but that stuff was cheap to get on the used market at the time. It did have some HDDs, and each computer had random video, sound and controller cards, power supplies and disc/disk drives. Well, at the time, this stuff was basically worthless. I slowly got rid of it all, it was taking up too much space. I've been kicking myself ever since. If I held on to it until now, I could have cashed out pretty good on it. But I wished that I had held on to at least ONE of those computers for myself. By the time I realized I wanted a computer of that vintage, the prices had already started to go up.
Over the last few years, I occasionally would get my interest sparked and take a look on eBay for a motherboard. Then I would quickly become disenchanted by the prices. Once or twice I came ::this close:: to pulling the trigger on something, but chickened out. I have so many computers in storage... What the hell do I need another computer for?! LOL
So I must be crazy, but I just watched a 486 build video on YouTube (as I sometimes do) and decided to check eBay. I forget how I decided to check for this specifically, but I ended up stumbling upon this Biostar motherboard. I have a little bit of a soft spot for the Biostar brand, so I was immediately drawn to it. And the price was good, too! So I sort of loosely decided a while ago that if I ever do a real DOS machine, I think I'll go for a Pentium over a 486, just so I can do more with it in my own era of gaming. Which leads me to why Socket 7 motherboards are so awesome.
Socket 7 is kind of ridiculous because it can accept such a wide range of processors. Intel, AMD, Cyrix and more! It can even accept Socket 5 CPUs! (To put that into perspective, picture a motherboard today supporting rival CPU brands, and CPUs of the last generation). And because of the era, you're likely to find many things integrated on the motherboard. Like an IDE and floppy controller so you don't need a controller card. It was on the verge of a lot of things, so you may find SD RAM. You might even get an ATX power connector which is a real plus to have.
The board I just nabbed is almost perfect. It has floppy and IDE, DIMM and SD RAM (which is great because I have a ton on hand), a coin cell battery for the CMOS (some older PCs need to be modified to fit a battery), a PS/2 mouse port, and of course my fondness for the Biostar brand. The only thing I wish it had was an ATX 20-pin power connector. It actually has a spot on the motherboard for it, but it's not populated. I mean, I can make do with out it. But I wonder if I could add the 20-pin header. Anyways, it also comes with a Pentium 166 with the heatsink and a stick of RAM. I don't know the capacity of the RAM, but I don't really care since I have a huge pile of SD RAM (and I believe they're all backward compatible, so I should be all set). The CPU isn't crazy expensive or anything, but this auction was only $50. Usually you can't even get just the bare motherboard for that price, let alone with a CPU and RAM!
The side of the road PCs that I mentioned above, I had saved various parts from. I did save one single VGA PCI card that I held onto for years. I can't remember if I finally got rid of it, but I guess I must have because I just looked for it and couldn't find it. Since I'll need a video card to confirm this board works when I get it in, and since I apparently got rid of my only PCI video card, that means I had to get one...

A Compaq branded S3 Verge/GX. I'm not sure if this will be the final video card for this build, but these seem like a good choice for a DOS machine and I was able to get this card for pretty cheap.
I have spare ATX power supplies on hand, so I picked up a cheap ATX to AT power connector. Again, so I can test the board right away when I get it in. I'm not sure what my final set up with be. I'll probably get a modern ATX power supply to use along with adapters. But if I ever come across a good brand AT power supply, I wouldn't rule out the possibility of recapping and using it. Although ATX is always going to be the safer choice, I suppose.
The big problem, as dumb as it seems, is going to be the case. I can't exactly shop locally for an AT style case. I've never come across one in a thrift store around here. And they're way too expensive on eBay. I might end up using an ATX case, if I can find one that looks right. Unless I can come up with some other idea.
I'm also not sure what I'm going to do about a sound card. I have a Sound Blaster 16 Wave Effects ISA card, but I actually got it for my Windows 98 PC and I might want something more period correct for this. But I don't know, those Sound Blaster 16 cards are expensive!
For the OS, I actually have a new in box DOS 6.22 (I also have a boxed DOS 5.something). I was going to get rid of it, now I'm glad that I didn't! Years ago I had Windows 3.11, but I sold it to someone here. Oh well. I have a CD ISO image for 3.11 that I used in DOS Box, so I'm sure it'll work on a real PC. I'm not sure what I'm going to do for storage. I may want a real HDD in there, I don't have any period correct HDDs on hand though. I may also want a CF solution in there. It might be nice to have a CF card mounted in an external drive bay, that I can easily swap out to change OSes. For example, maybe have DOS and Win 3.11 on one, and fuck around with Windows 95 on the other.
I'll have to pick up another 5.25" floppy disk drive, since the only beige one I have I'd like to keep in my Windows 98 PC. And somehow I ended up with three black 3.5" FDD, so I'll have to find a beige one. Or possibly just a beige face plate that fits. I have a few spare CD-ROM drives, though they may need Retro Brite. I may have to keep an eye out for something more period correct, though.
So this will probably be a really slow build. I'll definitely test the board out right away after I get it in. But after that, it'll probably take some time for me to complete. So I'll post updates as I go along.