That PSU placement is a bit of a problem for where most ATX boards put their CPUs, for getting a decently large cooler on. So probably want to think about what you can get a decent small cooler for and work back from there. Though a slot CPU would fit under it maybe.

One thought is a 775 board, with an L series Xeon 54xx on it modded from 771, then you can use one of the short "pancake" intel core coolers on it, think they were original to core celeron 4x0

I did notice that.

I have a spare SFX power supply with adapter plate. Need to do some measurements to understand my options.

soupapes wrote on 2023-11-20, 21:31:

Might go for a sleeper build.

Please don't 🙁. Cooling will certainly be a problem. Also, original IBM PSU has non-standard dimensions (I have similar Aptiva with slot-A Athlon). You might have to opt for SFX PSU with adapter.
There should be a sticker with specs somewhere at the bottom. By the front stickers I'd say socket 7?

stef80 wrote on 2023-11-21, 02:44:

There should be a sticker with specs somewhere at the bottom. By the front stickers I'd say socket 7?

Agreed, Pentium MMX is pretty much always Socket 7

That was originally a Win95 computer with Intel MMX 200 Pentium. Some came with AMD K6 333mhz CPU.
The Original motherboard was a Socket 7 that could support Intel or AMD CPU. It had an onboard ATI Rage GPU chip
And onboard Audio.
You could source an original motherboard on eBay or Maybe turn it into a Win98 computer for Better Gaming performance by adding a full size ATX motherboard ( Bx440, Socket 370, or AMD K7 ) it won’t be a perfect fit inside the case but it could be made to work.
You might have to upgrade the Power supply to.

But I really like those white box 1990’s IBM computer cases. They made the cases look so clean and simple.

I think it had a Pentium MMX due to the sticker in the case.

The case points to model 2137-E30

And we do have a project, nothing too exciting, its just a budget build.

I bought MSI motherboard and Ryzen 5 4500 with 16gb.

Its a work in progress, waiting for upgrades...

The SFX PSU with an adapter plate provide good clearance for the CPU fan.

Bought in amazon a cosmetic product, Oxidizing Cream level 40, and works great to perform some whitening of plastics. After a few hours exposed to sunlight the case now looks much better, the yellow areas are now white.