I think I have a 915/skt478 mobo too, though mine still runs classic DDR1 and is PCI-E + AGP. Asrock P4Dual-915GL.

As for Cedar Mill on 865 - IIRC they might use the same CPUID? I know I was looking at my MSI 865PE Neo3-V's CPU list and found no mention of the 631 being compatible.
Despite that, it did POST with the 631 and detected it properly (and enabled HT properly).

Socket3 wrote on 2023-08-29, 17:58:

On the other hand, I've had little to no luck upgrading OEM systems that use the chipsets you mentioned. I tried swapping dual core chips into Dell Optiplex, IBM Netvista and HP i915 or i925 prebuits with no success..... maybe this is mostly an OEM thing?

This may no longer be the conventional wisdom, but way back then, the general understanding was that the i915/925 had removed dual-processor/core support. The i865 had it, somewhat 'unofficially' (i.e. probably shared too much design with a Xeon chipset), then when somebody in Taiwan cooked up a way to design a dual-processor i865 board, Intel was very grumpy and made sure that you couldn't do the same thing with the i915/925. Then, of course, Intel launched dual-core chips (perhaps in response to AMD - I can't remember who came up with dual-core single-socket systems first) and this became a problem, so they launched the i945/i955 to bring dual-core support back.

(This is also what let... most of the Taiwanese manufacturers... make LGA775 i865 boards that supported at least hotburst 90nm dual-core CPUs to give people with AGP/DDR1 an upgrade path to dual-coreness.)

Did somebody in Taiwan actually find a way to get dual-processor/core support out of an i915 while I wasn't paying attention?

PcBytes wrote on 2023-08-29, 21:11:

Despite that, it did POST with the 631 and detected it properly (and enabled HT properly).

It may depend on what stepping that 631 was, the later ones had newer VR06 configuration and the earlier ones had VR05A which is closer to Prescott and may work without official support.

Socket3 wrote on 2023-08-29, 17:58:

I also remember messing about with an Asus - can't remember what model, but it had an intel 915 chipset - P5GD or P5GD2 perhaps? - the system I liberated it from came with a Celeron D, and despite no mention of compatibility on Asus's website, the board booted up and ran fine with a Pentium D 925....

I guess it could be ASUS P5GD2-X based on i915. But I've never had one to test it with Pentium D 65nm

Is it safe to use Cedar Mill with Gigabyte GA-8IPE775-G (rev. 1.1) ?

RiP wrote on 2024-01-04, 19:54:

rev. 1.1

Only 1.2. They share BIOS so it’s a hardware limitation.

I have a ThinkCentre A51 USFF coming tomorrow, model 8107-71G. This is an early-ish 775 machine with a 915G chipset onboard, but it's also a transitional model, Lenovo taking over most of the IBM stuff past this point. Somewhere in 2005 there was a microcode update added to a previous BIOS release (2GJT17A) from the release notes.

12GKT17A/2GJT17A
2- Updates video BIOS to build number 1233
3- Updates microcode update files
4- Fixes a problem where the system reboots continuosly with new
5  processors
6- Fixes potential 0162 errors
7- Fixes a problem where the system hangs during S3 resume 
8- Fixes intermittent 0197 error
9- Implements Intel 915/925 specification update

Using MCExtractor: https://github.com/platomav/MCExtractor I was able to figure out I have the following CPUIDs in the latest update file:

F62 is a Cedar Mill, so sufficed so say I should be okay there getting an earlier stepping.
The interesting one is F61. I can't for the life of me figure that one out, but CPU-World's CPUID DB has F61 down for a Xeon 5060? That makes no sense as the 915 doesn't support dualcore.

Did some of the Xeon codes overlap the Extreme Editions?

BitWrangler wrote on 2024-03-22, 03:44:

Did some of the Xeon codes overlap the Extreme Editions?

They might have but I don't think this applies to this, the only extremes that can work on that machine are the Prescott ones and those are a separate cpuid I believe.

Sorry if I'm necroposting here, but I am trying to research potential pin mods or tape mods for getting VRM Config 06 chips working on 04A systems. I have a few Cedar Mill P4s on the D0 stepping but unfortunately they don't work on my zd8000 as-is. I'm fairly certain it should be possible to make them work without the need of a BIOS update?

What usually helps is cutting off the trailing decimals by rounding up or down. This is in general so not specific voltages you need getting mentioned, but examples... say board will do 1.48 or 1.47, CPU demands 1.475, so mask off the .005 and try it so the board gives it 1.47 or go the other way and monkey the pins for it to pick up as 1.48... works on 370 stuff too where something wants 1.75 and vreg does 1.7 or 1.8

Sudos wrote on 2024-03-22, 03:08:

I have a ThinkCentre A51 USFF coming tomorrow, model 8107-71G. This is an early-ish 775 machine with a 915G chipset onboard, but […]
Show full quote

I have a ThinkCentre A51 USFF coming tomorrow, model 8107-71G. This is an early-ish 775 machine with a 915G chipset onboard, but it's also a transitional model, Lenovo taking over most of the IBM stuff past this point. Somewhere in 2005 there was a microcode update added to a previous BIOS release (2GJT17A) from the release notes.

Copy code to clipboard

12GKT17A/2GJT17A
2- Updates video BIOS to build number 1233
3- Updates microcode update files
4- Fixes a problem where the system reboots continuosly with new
5  processors
6- Fixes potential 0162 errors
7- Fixes a problem where the system hangs during S3 resume 
8- Fixes intermittent 0197 error
9- Implements Intel 915/925 specification update

Using MCExtractor: https://github.com/platomav/MCExtractor I was able to figure out I have the following CPUIDs in the latest update file:

The attachment Screenshot_3.png is no longer available

F62 is a Cedar Mill, so sufficed so say I should be okay there getting an earlier stepping.
The interesting one is F61. I can't for the life of me figure that one out, but CPU-World's CPUID DB has F61 down for a Xeon 5060? That makes no sense as the 915 doesn't support dualcore.

Hi, did you ever get this to work with Cedar Mill? I also have a ThinkCentre A51 (8135-CTO) and was curious if it would work, I currently have Windows 10 32-bit with a P4 531, but have ordered a 631 and was wondering if it will work, so that I can get some Windows 11 action going 😁

Karbist wrote on 2023-07-21, 21:09:

It's rev 1.05 and looks like this: https://www.newegg.com/p/N82E16813131503 without the microcode it always halts on missing uco […]
Show full quote

W.x. wrote on 2023-07-21, 20:18:

Thank you for great news. What PCB revision is your P5GD1? BIOS version is latest? Did you try it without updating the microcode?
Are you planning to upload picture of your board to TheRetroWeb? Maybe, that modified BIOS would come handy for others. (including me 😀)

It's rev 1.05 and looks like this: https://www.newegg.com/p/N82E16813131503
without the microcode it always halts on missing ucode message and you have to hit F1 to boot and I don't think you can install x64 version of windows without cpu fully recognized.
patched v1014 bios :

The attachment P5GD114.rar is no longer available

Hi, guys! Thank God I've found this thread. I've been playing around with some old Intel Pentium 4 chipsets of mine, and I've come across the Asus P5GD1 Pro. I've already already updated to the latest bios version, a beta one. I would like to use a Cedar Mill. Can I use this version of the bios? The board is similar, although it always says PRO on it, like a sticker but it's definitely the same with the one on the RetroWeb. Thank you!

silv3r wrote on 2025-08-20, 19:35:

Hi, guys! Thank God I've found this thread. I've been playing around with some old Intel Pentium 4 chipsets of mine, and I've come across the Asus P5GD1 Pro. I've already already updated to the latest bios version, a beta one. I would like to use a Cedar Mill. Can I use this version of the bios? The board is similar, although it always says PRO on it, like a sticker but it's definitely the same with the one on the RetroWeb. Thank you!

P5GD1 Pro is the cut down version of P5GD1 with no IDE raid, not sure why they call it Pro.
and bios is different, here's the beta 1013.001 bios for Cedar Mill (not tested).

Karbist wrote on 2025-08-20, 21:07:

P5GD1 Pro is the cut down version of P5GD1 with no IDE raid, not sure why they call it Pro. and bios is different, here's the be […]
Show full quote

silv3r wrote on 2025-08-20, 19:35:

Hi, guys! Thank God I've found this thread. I've been playing around with some old Intel Pentium 4 chipsets of mine, and I've come across the Asus P5GD1 Pro. I've already already updated to the latest bios version, a beta one. I would like to use a Cedar Mill. Can I use this version of the bios? The board is similar, although it always says PRO on it, like a sticker but it's definitely the same with the one on the RetroWeb. Thank you!

P5GD1 Pro is the cut down version of P5GD1 with no IDE raid, not sure why they call it Pro.
and bios is different, here's the beta 1013.001 bios for Cedar Mill (not tested).

The attachment P5GD1-Pro.1013.rar is no longer available

Thank you so much! So the Pro is less for this board? Hilarious! Anyway, I'll test it right away. God bless you!

silv3r wrote on 2025-08-21, 18:56:

Karbist wrote on 2025-08-20, 21:07:

P5GD1 Pro is the cut down version of P5GD1 with no IDE raid, not sure why they call it Pro. and bios is different, here's the be […]
Show full quote

silv3r wrote on 2025-08-20, 19:35:

Hi, guys! Thank God I've found this thread. I've been playing around with some old Intel Pentium 4 chipsets of mine, and I've come across the Asus P5GD1 Pro. I've already already updated to the latest bios version, a beta one. I would like to use a Cedar Mill. Can I use this version of the bios? The board is similar, although it always says PRO on it, like a sticker but it's definitely the same with the one on the RetroWeb. Thank you!

P5GD1 Pro is the cut down version of P5GD1 with no IDE raid, not sure why they call it Pro.
and bios is different, here's the beta 1013.001 bios for Cedar Mill (not tested).

The attachment P5GD1-Pro.1013.rar is no longer available

Thank you so much! So the Pro is less for this board? Hilarious! Anyway, I'll test it right away. God bless you!

It works flawlessly! I've managed to get my hands on a Cedar Mill 651 running at 3.4 which I overclocked at 3.65 for now, I don't know if the board can take it higher but I'll try. It's way cooler than the other cpu, a Prescott 3.0Ghz, running around 50 degrees. This Cedar Mill is revision D0 which runs at 65W. By the way, I have to other Intel boards, Intel D865PERL and D875PBZ. Can I do anything to overclock the CPU beside the 4%? I've tried the ClockGen app but I couldn't set it right, I didn't find the right PLL. Anyway, another Asus P4C800 is on the way and my vintage collection is getting bigger. Thanks a lot!

Karbist wrote on 2025-08-20, 21:07:

P5GD1 Pro is the cut down version of P5GD1 with no IDE raid, not sure why they call it Pro. and bios is different, here's the be […]
Show full quote

silv3r wrote on 2025-08-20, 19:35:

Hi, guys! Thank God I've found this thread. I've been playing around with some old Intel Pentium 4 chipsets of mine, and I've come across the Asus P5GD1 Pro. I've already already updated to the latest bios version, a beta one. I would like to use a Cedar Mill. Can I use this version of the bios? The board is similar, although it always says PRO on it, like a sticker but it's definitely the same with the one on the RetroWeb. Thank you!

P5GD1 Pro is the cut down version of P5GD1 with no IDE raid, not sure why they call it Pro.
and bios is different, here's the beta 1013.001 bios for Cedar Mill (not tested).

The attachment P5GD1-Pro.1013.rar is no longer available

Coming back again to you for help! I've managed to get my hands on a P5GDC Deluxe which I think it is much better but after having updated to the latest bios, the Cedar Mill doesn't work, althought I had expected so. Could you help me mod the latest bios version for this board, please? Btw, does it run any Core 2 CPUs? I guess not. Thanks in advance!

To the Core 2 part, no, you need at least 945P board, or any 945 chipset family board, but late revision, that added support for Core 2 (most boards did). Even 945GC and GZ are for core 2, and, now shocker, even for 45nm. So yeah, you can put in E8400. Example of such board is Asus P5GC-MX/1333 . 955 doesn't support core 2, because they didn't bother to add support, as there was already 975 out. So some early boards with 975 chipset doesn't support it, while later ones do. Example is Intel Bad Axe board. It has a Intel AA code that mark revision, according it you can find out, if it support Core 2 or not.
Also 945 boards can support only Core 2 Duo, not Quad. From 965 above, it supports also Quad. First chipset that was Core 2 from basis was 965. There are no 965 boards without Core 2 support. But intrestingly , there are 975 boards without Core 2 support as I said, that is confusing lots of people, because they think 965/ 975 chipsets are core 2 chipsets. But actually only 965 is.