Did you connect both additional power connectors (4-pin and 6-pin)?

majestyk wrote on 2025-03-16, 14:32:

Did you connect both additional power connectors (4-pin and 6-pin)?

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Yes, I specifically try to use contemporary power supplies for P4 systems. It's a Hi-Pro that has been recapped, and I know it gives solid power.

Do you have a diagnostics card? If it says '-- --' it is bios/cpu/board related.
Or any beeps?
Do the Prescott based CPUs work in another board?

PD2JK wrote on 2025-03-16, 15:54:

Do you have a diagnostics card? If it says '-- --' it is bios/cpu/board related.
Or any beeps?
Do the Prescott based CPUs work in another board?

Yeah, CPUs work fine on other boards, and the diagnostics card I have just gives ----. Strange that it works with Northwoods though.

Turn it on without the cpu cooler and see if cpu gets warm.

Could the pins have different designations, i.e. does a Prescott have slightly other pin functions, and if so, I'm thinking of a dirty or malfunctioning socket.

Karbist wrote on 2025-03-16, 16:30:

Turn it on without the cpu cooler and see if cpu gets warm.

It's not getting warm. The PC shuts off after holding down power button for 5 seconds instead of instantly shutting off too, if that helps.

PD2JK wrote on 2025-03-16, 16:47:

Could the pins have different designations, i.e. does a Prescott have slightly other pin functions, and if so, I'm thinking of a dirty or malfunctioning socket.

That's what I'm thinking, that or the Prescott ready labeling was just a lie!

I seem to remember having that board at some point in the past. I have the drivers for it (as on retroweb)
It doesnt support Prescott core processors. I had a 3.06HT 533 CPU in it.

prescott needs bios microcode support and vrm support. your vrm might not be able to handle the voltage requested or the board may need a bios update.

The board matrix doesn't show Prescott support...where are you seeing it as Prescott-ready?

https://web.archive.org/web/20060930051921id_ … pport-p4478.htm

It looks like there is mATX version of this board: PT8MS
And in web archive there is A04 (even A05 from 02/01/2005) BIOS for it, which is described as "Update CPU micro code for CELERON D E-Stepping." (Celeron D is Prescott)
https://web.archive.org/web/20130518232708/ht … dex-1.htm#PT800

The question is, are you brave enough to try it? 😀
Or maybe the latest official bios can be modified - based on the fixes from the PT8MS version ?

IMHO: It isn't worth the effort. Prescott is only sometimes faster than Notrhwood when compared clock-to-clock and more power hungry and hotter...
For science maybe 😀

altarofmelektaus wrote on 2025-03-17, 02:19:

PD2JK wrote on 2025-03-16, 16:47:

Could the pins have different designations, i.e. does a Prescott have slightly other pin functions, and if so, I'm thinking of a dirty or malfunctioning socket.

That's what I'm thinking, that or the Prescott ready labeling was just a lie!

According to CPU-Upgrade, Prescotts are a NO-GO on this board.
https://www.cpu-upgrade.com/mb-Jetway/PT800DBP.html
FWIW, their info on CPU support (both official and unofficial) is relatively accurate.
The fact that so many Prescott CPUs have a big red mark next to them (unsupported) suggests this motherboard indeed probably never supported Prescott CPUs.

Perhaps Jetway intended to release support for Prescott CPUs later on (if, say, the board was released before they were available), but probably just didn't.

majestyk wrote on 2025-03-16, 14:32:

Did you connect both additional power connectors (4-pin and 6-pin)?

Wow, that's such a strange design!
I wonder why... or rather, what Jetway engineers were smoking at the time... for both a 6-pin Aux. power connector and a 4-pin 12V CPU power connector to co-exist on the same board.
FWIW, if there is a 4-pin 12V CPU connector, then the CPU VRM will almost certainly be using that.
I can only understand the 6-pin Aux. connector to be there IF there is something on the board that heavily uses either the 3.3V or 5V rails, like for example, an AGP Pro slot (where there are additional power pins.) Aside from that, it's probably one of the most useless connectors to have on a board. Looking at the Northbridge chipset heatsink on this board, it appears capable of handling no more than 10-15 Watts max of TDP... so not like there would be a need for an extra power for that.

altarofmelektaus wrote on 2025-03-16, 14:03:

I've heard something about motherboards with failing capacitors not wanting to run higher powered CPUs, and thinking maybe this has something to do with it? Caps don't look bloated, but they are definitely low quality.

Probably not a caps issue in this specific case... but you still might want to recap the motherboard if you intend to keep it / use it over time.
Jetway really like to use GSC / Evercon / Sacon capacitors A LOT, which are utter garbage. It's the same company that makes these, and the reason for the different names were because the company kept changing names to try to hide from the fact that they produced such garbage caps.

zyga64 wrote on 2025-03-17, 12:19:

IMHO: It isn't worth the effort. Prescott is only sometimes faster than Notrhwood when compared clock-to-clock and more power hungry and hotter...
For science maybe 😀

For gaming... yeah, probably not worth it indeed.
For non-gaming use and specifically for multimedia (video encoding / decoding), the extra L2 cache and SSE3 instructions do make it noticeably faster. The SSE3 helps even more for online use... just saying (as if anyone would still care to use a P4 in 2025 for browsing online... myself EXcluded 🤣 ).

altarofmelektaus wrote on 2025-03-16, 15:46:

Yes, I specifically try to use contemporary power supplies for P4 systems. It's a Hi-Pro that has been recapped, and I know it gives solid power.

Nice! 1-up 👍 for Hi-Pro from me too. They are well-designed and solid PSUs all around, often with very low noise & ripple on the output.

Isn't the 6-pin just intended for PSUs that don't have the 4-pin Pentium 4 power connector, like a compatibility thing? Or does it explicitly say in the manual that both need to be connected?

H3nrik V! wrote on 2025-03-21, 06:24:

Isn't the 6-pin just intended for PSUs that don't have the 4-pin Pentium 4 power connector, like a compatibility thing?

Not really, because motherboards that don't have a 4-pin 12V connector will then use 5V to power the CPU. The 6-pin connector provides two extra 3.3V lines and only one extra 5V line - hardly making a difference for motherboards that tax the 5V-heavy for power-hungry CPUs (e.g. "high-end" P4 Willamate & Prescott, also late Athlon XP T-bred and Barton cores.) I suppose one extra 5V wire is still better than none... but considering those 6-pin connectors are the same style as the AT connector, I don't think they are rated for currents as high as the style that's used on the ATX connector. So in reality, that extra 5V line might not be helping as much as one would anticipate.

momaka wrote on 2025-03-25, 17:01:

H3nrik V! wrote on 2025-03-21, 06:24:

Isn't the 6-pin just intended for PSUs that don't have the 4-pin Pentium 4 power connector, like a compatibility thing?

Not really, because motherboards that don't have a 4-pin 12V connector will then use 5V to power the CPU. The 6-pin connector provides two extra 3.3V lines and only one extra 5V line - hardly making a difference for motherboards that tax the 5V-heavy for power-hungry CPUs (e.g. "high-end" P4 Willamate & Prescott, also late Athlon XP T-bred and Barton cores.) I suppose one extra 5V wire is still better than none... but considering those 6-pin connectors are the same style as the AT connector, I don't think they are rated for currents as high as the style that's used on the ATX connector. So in reality, that extra 5V line might not be helping as much as one would anticipate.

That sounds reasonable, I just wasn't aware of which half of the AT power connector, that was used in the auxiliary plug.

I've seen that same connector show up on some Pentium 3 mainboards as well. Namely OR840 and XG-DLS.

I've seen those 6-pin connectors on some higher quality Slot-1 boards (Intel and IBM). I haven't seen them on anything newer though.

I think the original purpose of those 6-pin connectors was for the theoretically large amount of power that you *could* draw with lots of expansion cards. I do remember an IBM manual calling it out for that situation, anyway.
PCI 2.1 allows each card to draw up to 25W, and does not specify any division of that load between the voltage rails.
There could be some commercial/industrial application where somebody could have 5 identical PCI cards all pulling near 25W each, and if a lot of that was coming from 3.3V then the amperage would be especially high.

The only place I ever saw them used last was RDRAM based P4 and I think some early SDRAM based 478 boards (Aopen AX4Bs comes to mind). By the time 845 became standard it was phased out, as far as I remember.