There is a thread like this somewhere. Can't find it. But the TL;DR was: get a Pentium1 (like 133 or 166Mhz) because you can slow these down to 486 speeds. So these will run Pentium-era DOS games (like Quake 1, Wing Commander 3/4, etc) well, but when slowed down will also run 386 and 486-era games perfectly fine.

Even if you stay with the 486 dx4, you'll probably seriously bottleneck it with the ISA VGA. Unless "classic games" mean pre-3d ones that would get away with a slower rig.

Dr.Faustus wrote:

Motherboard (currently considering): Asus PVI-486SP3

This is a cool board, I have one too (brand new actually). The cool feature of this board is that is has ISA, VLB and PCI. If you're planning on just doing ISA video with this board then there are other boards more suitable. I'd use at least VLB graphics on this, try to find a good Cirrus Logic VLB or Tseng Labs ET4000 VLB, if that fails, go for PCI. Use ISA for sound instead (AWE32 or AWE64).

As you say you already have another 486, It's not like this one has to be games focused, I get it this is more of a test bench first, games second.
If it was me I'd ditch the USB and go with a network card, catch is you'll want to network the other machines as well.
It's file sharing is the only reason I use Win3x on my 486.

VLB graphics IS what 486's are all about but also $$$ PCI is just as good and cheap, ISA is worse but in your case free, hard call. See how the isa card handles Win95 and if its crap get a cheap pci card till you find a VLB card?
Sound, I'd go with something different just to be different, be it the standard SB16 or something else completely.
Cache I'd max out, just because I like maxing stuff out, plus it'll help in Win95

If you're interested I have this on eBay right now.

https://www.ebay.com/itm/183836328926

I had 2 of these but one of them didn't come in the box like the one I have on eBay. My friend wanted the one without the box, and just wanted the case. So I took the PSU and am in the middle of doing my own 486 DX4 build, that 250W "no brand" PSU so far has been solid. 25A on the 5v rail. Wooo. Currently at 100Mhz but I would love to go 120Mhz or 133Mhz AM5x86. But I need to verify my mobo can support it. I'm using an AT case that had a Pentium 133 in it but will be saving that for a future project.

For a video card, I went with a VLB since my mobo is ISA and VLB only. I have drivers for it (Trident TGUI9440) for Windows 3.1 but they don't seem to be working. Currently trying to track down different drivers. Another option, as mentioned above would be a regular PCI video card. Anything would work really if you're just doing DOS but it may be hard to find Windows 3.1 drivers. So a PCI card might no be "period" but it should give you the fastest experience just getting the image to the monitor.

Personally I would go with some SB16 variant. I had a 2000 series SB 16 Value I saved from eWaste and I was shocked to find that it works perfectly even in 16bit mode. MIDI is probably it's weakest point. I also have a "RadLib" AdLib clone from Tex-Elec that sounds like proper AdLib.

https://texelec.com/product/radlib-opl2-sound … sa-adlib-clone/

It should be possible to run both cards at the same time. But that's a project for the near future.

For storage I use this in any of my builds WIn98 and older.

https://www.amazon.com/gp/product/B074RG66ZV/

I have 4 or 5 of them, they are dirt cheap. I use cheapo 8GB SD cards and they do great on 40 and 80 conductor IDE cables. So far no defects or failures on these. I've had very bad luck with the IDE-CF adapters. I've tried 3 different ones and none of them worked for me. I think it has to do with the "removable media" bit flipped to on, on most CF cards.

If you have a 3D printer there are various mounting options for them as well on Thingiverse.

Apparently (and please tell me if I'm wrong here) L2 cache is best utilized based on your system RAM? 256k should be perfect for 64megs of ram and 512k is great for 128megs of ram. My mobo came with no L2 cache, but I believe I have the right chips and will be installing them soon. I plan on doing a benchmarking video on it when I add them. IIR I have 256K to install and I have 64megs of Fast Page installed. Even without the L2 Cache Duke Nukem 3D is totally playable with a little slow down here and there at highest graphics settings as the stock 320x200 (or 240?).

The suggestion of rocking something faster and slowing it down is a very good one. Personally I think one of thebest CPU's for this is a K6-2 500Mhz. You can change the clock and the multiplier in the BIOS or use tools like "setmal" that Phils Computer Lab covered. Personally I just use the BIOS settings. You can also enable and disable cache in addition to setting the clock all the way down to 166Mhz or up to 500Mhz. Only down side is Super Socket 7 mobos are a little harder to track down depending on your budget.

Anyway hope all this info helps as I'm going through it now with my 486 DX4 build.

I would suggest
VGA - definately some PCI card, almost any would be faster than ISA card
HDD - would advice to go for an SD-to-IDE adapter, rather than CF. I had lots of trouble making CF-to-IDE work in my own 486 and post, and what helped was getting an expensive Industrial-grade CF card (55 USD). SD-to-IDE worked absolutely without issue in my other 486 build. Your board has two IDE channels on-board so the front panel LED for disc access should blink just fine, I would have it as an only master on the channel. Downside of this SD adapter would be that (1) you need to figure out some mod to mount it inside the case and (2) the SD card would not be easily accessible, but its 15 USD solution and without trouble.
PSU - would opt for new ATX PSU of some sort (be quiet! personally), and an ATX-to-AT adapter and a switch like this (you can get those at almost every electronics parts shop), that is in my opinion a very safe bet
Audio- AWE32 ISA card definately
With some low-rpm CPU fan (running at 7V or 5V), you can have basically a noiseless pc...

Note on RAM - its not going to be easy, sourcing large capacity simm modules for just two slots....
Note on cache - be careful with cheap ebay SRAM chips, I have had trouble myself (128K x 8 DIP-32 chips in particular)

Getting a NEW PSU is probably better than a New Old Stock AT PSU. But remember that AT PSU's are much stronger on their 5V side than their 12V side. If you want to adapt a modern PSU, I would be sure it has a bare min of 20 amps on the 5v side. 25amps would be better. I just looked and EVGA has a 500W PSU that claims 20A of 5V power. A 200W AT PSU would have the same amperage on 5V. Just something to keep in mind.