I haven't had a Deskpro 4000, but as a tip in the meanwhile, several people do & have posted about them. You can search by google like below, and by the forum's search. They have different advantages. Google doesn't need you to be precise, whereas the forum's search skips people's sig files. Cheers.

https://www.google.com/search?safe=off&q=site … AQ+DESKPRO+4000

Welcome 😀

Is this the board?

If so it's a Compaq motherboard based on the Via VP2 chipset (which has a VT82C595 northbrdige). The chipset definitely isn't the problem, this is a good 1997-era allround chipset. For K6-2 support there are two main considerations:

1) Voltage: the K6-2 wants 2.2V. It will survive 2.5V, anything over that risks toasting the CPU.
2) BIOS support. Not always necessary, some boards will fail to identify a CPU but run fine. Others do run but with features disabled. Some refuse to run at all.

Now, just the model number indicates that the board comes from some or other Deskpro 4000, probably a 4000 5233MMX. Unfortunately there were many of those and most Compaq documentation is based on exact model number. Even there, OEMs rarely if ever give out-of-original-spec upgrade help, so your best bet is some or other community site.

That said, the board definitely does 2.8V as it's rated for Pentium MMX. That's not a voltage you want to run a K6-2 at for long periods, but you can do a quick test to see what the board does with it. Just be sure to verify Vcore asap if it does run.

Assuming it does run and delivers an acceptable voltage to the CPU, then there's the speed setting. A better pic might help there. Assuming you're stuck with max 66MHz FSB, the setting to aim for is 2x66MHz, as later (CXT) K6-2 >=400 interpret the 2x as 6x, so your CPU will run at 6x66MHz=400MHz. If you can set higher FSB (Via VP2 definitely supports 75MHz and usually works at 83MHz too - but that does not mean Compaq has implemented it!) you can do 6x75MH=450MHz.

Maybe a good high-res pic of the board, particularly of any jumpers or dipswitches, might help.

Yes! That is it.

I didn't think to get shots of the whole board but I might have some from when I did some work on it awhile back. But the only settings I've seen while looking over the board is the setting for the speed of the cpu and all 66 mhz bus. Seriously wow you guys know your stuff thank you I'm still getting into retro computers and I've always wanted to make this thing a killer for its era.

These are the pics I have for now, I'll need to dig more for the older ones.

Edit, I have no idea if I need to put licenses on the pictures if I'm the one who took them. Sorry

I'm a little pessimistic for K6-2 support. From what I can see on the pics the board has one transistor for voltage regulation with a heatsink on it and no chokes anywhere near so I'll assume it's a linear voltage regulator.
If this is true it is likely the board can not supply enough current to operate a K6-2 CPU. The Pentium MMX 233 is Intel's most power hungry S7 CPU drawing ~6A and that's probably around the max those boards were designed for. With more power hungry CPUs like AMD's K6 lineup board on the horizon manufacturers switched to beefier power designs with switching voltage regulators since those are more efficient and get less hot.

That being said if the board supports 2.5V it won't hurt to try wether it POSTs.

Great documentation on the case - had forgotten about that. Unfortunately looks like you're out of luck. No voltage jumpers/switches at all. That gives two options:

1) system is only designed for Pentium MMX and so hard-wired for 2.8V.
2) voltage regulation is controlled by BIOS so CPU needs to be supported by BIOS, which it isn't.

Plus as Doornkaat says, the VRM doesn't exactly look very powerful. That said, there's not such a delta between P233MMX and K6-2. A P233MMX draws 17W, a K6-2 400 does 22.7V - and I suspect that's the old AFR model, not the newer AHX (CXT core), which runs cooler. The AFR doesn't remap 2x to 6x multiplier, so would only run at max 233MHz anyway. Still, without a voltage regulating interposer, you don't want to use a K6-2 on this board I'm afraid, regardless of current draw.

Setting the correct multiplier can be done by connecting socket pins W35 and V36 on the back of the board. This turns the setting for
1.5x/3.5x into 5.5x
2x/6x into 4x
2.5x into 4.5x
3x into 5x.
But yeah, microcode voltages and current...

Btw: Even though 17W vs. 22.7W is only a ~33% increase in power consumption according to AMD the K6-2/400AFR draws 11,25A under full load. That's ~87,5% more than the Pentium1 MMX 233 and certainly out of spec for this board. I believe all 400MHz models are Chomper XT core that runs 6x on the 2x setting. Chomper (non-XT) only went up to 350MHz afaik.

Ahh oh well. I didn't think I could push it any further but was worth a shot. I know what's in there is still pretty good, overall I have sunk under 50 usd into it. It has 384 MBs of ram, then graphics card is a s3 virge so not great. I ordered an ati 5250 128 so it should do pretty good. Anyway I have another project that's a pentium 2 and is actually a board I can configure.
Anyway thank you for the info on this. I still might try and find a super socket 7 so I could play around with a k6-2 or 3 maybe.

playereric wrote on 2020-01-22, 21:42:

Ahh oh well. I didn't think I could push it any further but was worth a shot. I know what's in there is still pretty good, overall I have sunk under 50 usd into it. It has 384 MBs of ram, then graphics card is a s3 virge so not great. I ordered an ati 5250 128 so it should do pretty good. Anyway I have another project that's a pentium 2 and is actually a board I can configure.
Anyway thank you for the info on this. I still might try and find a super socket 7 so I could play around with a k6-2 or 3 maybe.

The Virge gets lots of bad press due to its incomplete 3D feature set but assuming it doesn't have the brightness bug (colours washed out, black looks grey) it's a great 2D DOS card. Overall that system is great for getting into DOS gaming.

It's a perfectly acceptable Windows 2D chip as well. The period-correct way to upgrade for 3D would be to add a Voodoo 1/2.

My first job in the early 2000's was at a company that had loads of Deskpro 2000's and 4000's. Good solid office workhorse PC's never had a problem with them. The IBM P3's on the other hand...
If your getting a P2 leave that for the WIn9x games.
The 233MMX will make for an excellent dos gaming PC which the S3 chip can handle no problem.