luckybob wrote on 2025-05-09, 15:14:

The 5/12 processors have integrated voltage regulators. the 2.8v cpus do not. If a slot-2 motherboard has separate voltage regulators AS YOUR DOES, it means it is designed for the 2.8V processors.

The 2.8V Version with external VRMs can use 5V or 12V VRM moduls? Why different values? Confusing...
And boards from compaq for example dont have external VRM ports.

Yes, the voltage regulator is correct. It can accept 12 or 5v regulators. They output the 2.8v that the chips expect.

Now the 12/5 CPU are directly wired to the power supply and use their internal regulators. That's why you can't mix them.

These regulators are artifacts from the pentium pro era. Where they drew power from the 5v rail and output 2.8v for the cpu.

The pentium 2 xeons used the same regulators. But the switch to 12v as a cpu power source was forged by the p3 xeon. And rather that redesign everything, they just made the new regulators accept 12v input as well as 5v.

And because 99.9% of these xeons were sold to oem, and the intel just decided to integrated the arm on the cpu card to make them happy. You had to be a BALLER to have a dual xeon at home or be ultra special to get one as a workstation. So they didn't care to really offer them to the common rabble.

IT IS POSSIBLE, a 12/5 cpu might not blow up in a 2.8v board. But these parts are just too rare to fuck around with. So I apologize for shouting.

thanks for explanation. I got it now. I agree its to rare to mess up. Than i need to search again for a xeon pair.
I wish intel had design this with a jumper where you switch between external or onboard.

Intel is not a stupid company. (usually)

The 12/5 chips SHOULD NOT blow up if inserted in a 2.8 board. Other way around? most likely. Again, considering the cost of the parts involved and their scarcity, its just not worth it to try, imho. In a properly designed system, an incompatible cpu wont kill anything if inserted into the wrong motherboard. it just wont post. If I was a betting man, I would wager a 75% chance it just does nothing, and a 25% chance of fire.

In THEORY... if you bypassed the onboard regulator, and gave the cpu the desired 5 OR 12v. It should IN THEORY work. I'm also willing to bet there will be other required modifications to make that work and I have zero desire to find out. like pulling certain lines high or low to tell the chip its in a correctly powered socket. i'm going to wager, its like plugging a Tualatin P3 into a Coppermine motherboard.

This build is going to be Awesome if it ever gets built.
Makes me want to take out my Dual CPU motherboards and put one together but I don’t have all the spare components either.

Did some cablework and get Fans installed.

Will the SL3CE work on this board with 12V RMs?

Seller missed shipping me the VRMs, but they arrived now. They were still factory sealed. So i think the Mainboard was never used before.
Hope the caps are good quality.
I was thinking PCI-X is PCI-X but the controller i bought dont fit in the slot... Server stuff is just strange.

Have you tried fitting the card outside of the case. I've had that issue before where the case was slightly tweaked and I had alignment issues with expansion cards

Jackhead wrote on 2025-05-13, 13:38:

I was thinking PCI-X is PCI-X but the controller i bought dont fit in the slot... Server stuff is just strange.

That is not PCI-X, but a normal PCI slot with a RAIDport III socket connector.

https://ebay.us/m/rZmUvO

That's an example of the card for that slot.

It's super easy to get it mixed up with pci-x.

As above... https://storage.microsemi.com/en-us/support/_ … /raid_guide.htm and Adaptec ARO-1130U2 SCSI RAID controller drivers for Windows 98SE

Think that's pretty much it for RAIDport III cards, so if you're planning for SATA storage then look elsewhere.

Two new CPUs, hope they are correct now. Pulled from a HP Server. They are 700MHz FSB100 with 1 MB L2 . and they are 2,8V

perfect.

The tabs are removeable. the rivet just needs to be cut off. Sometimes it gets in the way. And a simple pan-head screw/nut can put it back if its really required someday.

You can still install that pci-x slot into normal pci slots. normally. The bottleneck will be the pci bus, but there's not much you can do about it.

Also, dont forget a fan for the bottom cpu. The intel brackets are poorly designed and for some reason only cool the top CPU. The best solution is to attach a 120mm fan to the side. maybe 3d-print a shroud? (or use cardboard)

Of course the cooler on the CPUs has no space and conflict with the caps...

The Foxconn cooler would work, when I can get that long screw out

Yup. This is totally normal.

Ok the foxconn heatsinks are installed on the 700 Xeons .
I think it's time for the the first system start! For testing I build me a ATX adapter with an AT plug breakout for the aux connector.
I will first try without the AUX connected, than i can also measure the volatge on each pin to be sure anything is correct.
Still don't know if I need that AUX connected, so first testing.

Jackhead wrote on 2025-05-16, 13:45:

Ok the foxconn heatsinks are installed on the 700 Xeons . I think it's time for the the first system start! For testing I build […]
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Ok the foxconn heatsinks are installed on the 700 Xeons .
I think it's time for the the first system start! For testing I build me a ATX adapter with an AT plug breakout for the aux connector.
I will first try without the AUX connected, than i can also measure the volatge on each pin to be sure anything is correct.
Still don't know if I need that AUX connected, so first testing.

NEED? no, not likely. Advisable? yes.

8/10 of the atx aux connectors will be wired like this: https://allpinouts.org/pinouts/connectors/pow … /atx-aux-power/

be warned, its not 100%. the XG-DLS from ASUS uses a similar, but special pinout. (i had to remove one of teh 3.3 wires)

No magic smoke, but i got some beeps, 1-5-2-1 , i guess something wrong with CPUs or RAMs..
I checked the manual but the code is not there.

edit:
Ok i replaced anything and I got a post! Its alive 😀
2x 700MHz P3 Xeon and 2 GB RAM, thats a good start!

god, those wago connectors are just awesome.

If this was my system, i'd look into making a rear exhaust fan shroud. I'd go out of my way to use clear plastic, you dont want to hide those big beautiful processors. ^.^