I would go 486 DX4/100 Overdrive. If the board can do 3.3volts then you can just do DX4/100.

The intel DX4s are the fatest. Unless you go AMD 5x86 or Pentium Overdrive.

For me DX4/100 sounds good.

Is there a way to tell if it'll do 3.3v? It definitely has a label that states how the jumpers are configured for a "DX4" processor. There's a lot of 1994 dates on the motherboard itself, so it should fall in that range? I don't see a jumper for that though (unless this is done automatically when selecting the CPU speed switches). It came with one the of the later P24D DX2-50's

Probably sticking to Intel processors for this one. Pentium Overdrive was a consideration but I have plenty of Socket 5 boards/processors if I want to scratch that itch and I definitely did that back in the day. I always wanted to do a 486 Overdrive for some reason, but it seems a waste if it'll natively handle a DX4/100.

Isn't the usual drill to get a AMD 5x86 P75-133 that's meant for 4 x 33 and get it to run stable at 4 x 40 MHz FSB?

The AMD 133 might be about as available as the Intel, since it was produced in far greater numbers. AFAIK, any board should take it, being just a plain 486. If it gets the 4 x multiplier right.
The Cyrix counterpart, maybe not so much.

If even the silkscreen says DX4, then to the best of my understanding, the board definitely should do 3 volts. You can probably spot the voltage regulator on the board. What else is it doing there?
You just need to download a jumper manual to make sure it's configured correctly, but you have to download a manual anyway.

Never quite understood the appeal of the Pentium overdrive in retro, apart from being a pose and rare.

Of course, don't forget to max out and tweak RAM and cache, if there's any to be done!

Is your 486 CPU soldered to the board or in a socket?

Anonymous Coward wrote on 2022-04-13, 09:24:

Is your 486 CPU soldered to the board or in a socket?

They did that to 486s at Compaq?!?

Yes, a socket usually helps 😉

Biggest potential issue is that some OEM systems have BIOS that only allow boot with known, supported CPUs. Not sure if that's the case with this Compaq Prolinea, but I'd recommend checking before shelling out on new hardware. Which exact model Prolinea is it?

Oh, and regarding 5x86 vs Pentium Overdrive - what works best depends on what you want to do with it. The Pentium has a far more powerful FPU and can run 586 code. The 5x86 are faster in ALU code but can't run 586 code. So if you want to run Windows XP on your 486, or want to play Quake slightly less hideously slowly, the Pentium Overdrive is the way to go (if supported). In almost all other cases, a 5x86 will be faster, if supported.

Anonymous Coward wrote on 2022-04-13, 09:24:

Is your 486 CPU soldered to the board or in a socket?

It's in a socket (socket 3). Like I said, it appears to be a really late 486.

Cuttoon wrote on 2022-04-13, 09:12:

Isn't the usual drill to get a AMD 5x86 P75-133 that's meant for 4 x 33 and get it to run stable at 4 x 40 MHz FSB? […]
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Isn't the usual drill to get a AMD 5x86 P75-133 that's meant for 4 x 33 and get it to run stable at 4 x 40 MHz FSB?

The AMD 133 might be about as available as the Intel, since it was produced in far greater numbers. AFAIK, any board should take it, being just a plain 486. If it gets the 4 x multiplier right.
The Cyrix counterpart, maybe not so much.

If even the silkscreen says DX4, then to the best of my understanding, the board definitely should do 3 volts. You can probably spot the voltage regulator on the board. What else is it doing there?
You just need to download a jumper manual to make sure it's configured correctly, but you have to download a manual anyway.

Never quite understood the appeal of the Pentium overdrive in retro, apart from being a pose and rare.

Of course, don't forget to max out and tweak RAM and cache, if there's any to be done!

I don't really care about cutting-edge performance in this. I'm really just upgrading to have some fun and to have enough overhead to run a few DOS games properly. I'm not in this for the flex or anything...it's just what I'd have done back in the day so that's where I'm headed with this build. I just don't know/remember enough about 486 quirks and I wanted to make sure I wasn't buying the incorrect processor upgrade.

The jumper manual is factory printed on a large sticker and on the inside of the PC. So, there's really no question about how it needs to be configured. It was actually more helpful than the manual I downloaded.

_tk wrote on 2022-04-13, 19:46:

[...]

I don't really care about cutting-edge performance in this. I'm really just upgrading to have some fun and to have enough overhead to run a few DOS games properly. I'm not in this for the flex or anything...it's just what I'd have done back in the day so that's where I'm headed with this build. I just don't know/remember enough about 486 quirks and I wanted to make sure I wasn't buying the incorrect processor upgrade.

The jumper manual is factory printed on a large sticker and on the inside of the PC. So, there's really no question about how it needs to be configured. It was actually more helpful than the manual I downloaded.

Well if you want to stay completely in spec, just follow the sticker.

If you want to push the envelope beyond what the sticker says, we need more info - like exactly which Prolinea it is.

Don't know too much about Compaq. Some OEMs had rather strict, exclusive purchase agreements with certain component suppliers, affording them a discount.
What about Compaq - did they ever use non-Intel CPUs back then?