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Pentium 3 slot 1 700mhz compatibility issue (?)

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Reply 20 of 31, by bunghole102

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NeoG_ wrote on 2026-03-24, 22:38:

I just thought the freezing BIOS page could also be a corrupted CMOS - In which case clearing the CMOS and making sure you have a good CMOS battery may help

The CMOS battery is new and I already cleared it with the jumper JP5 on the motherboard, still no luck on that.

Reply 21 of 31, by rasz_pl

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bunghole102 wrote on 2026-03-24, 15:28:

every time I try to enter that menu the machine locks up on me, and trying to navigate the menu with the keyboard causes strange beeping to come from the PC speaker. Any idea what that's about or how to fix it?

so it locks up the moment you enter the menu, before you even try changing anything?

bunghole102 wrote on 2026-03-24, 15:28:

trying to navigate the menu with the keyboard causes strange beeping to come from the PC speaker. Any idea what that's about or how to fix it?

so its frozen when entering menu/after it draws the new submenu, and pressing keys cases beeping?
Now that is exciting! Sounds like BIOS is unable to communicate with the clockgen chip and hangs because bios author didnt/badly implemented error handling and code is spinning in place.
That beeping is BIOS letting you know keyboard buffer is full and cant take any more key presses, its full because whatever routine supposed to read it and handle keys (the graphical bios menu routine) is busy, its busy because BIOS code handling i2C is busy.

Clockgen is IC Works W124G https://theretroweb.com/chips/4406 (acquired by Cypress Semiconductor in 1999). Communication happens over i2C bus.
Now considering the other fact about your 550mhz Pentium 3 also unable to boot at 100MHz, and this is controlled by CPU pin hard linked directly to clockgen SEL100/66# pin, and it points even stronger at W124G being defective in some strange way.

Im surprised this board works at all 😮 What would be a failure mode of a clockgen chip that makes it ignore two methods of setting clock, but still allow to operate outputting slow FSB and all other corresponding clocks correctly??? The only cosmic coincidence would be unconnected pins 16 and 17 and/or 18.
afaik IC Works W124G is unobtanium. You would have to salvage one from another board. One board I know that uses it is ABit BH6. I even have one for parts 😀

For starters do this experiment:
-turned off computer
-put your finger on W124G, its a chip between PCI slot and battery
-press gently but firmly 😀 keep constant pressure on the chip
-power on computer
-tell us if your Pentium 3 550mhz booted up at 366 or 550 MHz?

If that works then you got lucky and clockgen simply developed some cracked solder joints on pins 16/17/18, resoldering all of its pins will fix the board. If not the board is broken in some other stranger ways.

https://github.com/raszpl/sigrok-disk FM/MFM/RLL decoder
https://github.com/raszpl/FIC-486-GAC-2-Cache-Module (AT&T Globalyst)
https://github.com/raszpl/386RC-16 ram board
https://github.com/raszpl/440BX Reference Design adapted to Kicad

Reply 22 of 31, by NeoG_

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rasz_pl wrote:

Now considering the other fact about your 550mhz Pentium 3 also unable to boot at 100MHz, and this is controlled by CPU pin hard linked directly to clockgen SEL100/66# pin, and it points even stronger at W124G being defective in some strange way.

I think I and maybe others thought OP was able to try and boot at 100, but it sounds like so far the 100fsb option hasn’t even been selected to attempt it

98/DOS Rig: BabyAT AladdinV, K6-2+/550, V3 2000, 128MB PC100, 20GB HDD, 128GB SD2IDE, SB Live!, SB16-SCSI, PicoGUS, WP32 McCake, iNFRA CD, ZIP100
XP Rig: Lian Li PC-10 ATX, Gigabyte X38-DQ6, Core2Duo E6850, ATi HD5870, 2GB DDR2, 2TB HDD, X-Fi XtremeGamer

Reply 23 of 31, by bunghole102

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NeoG_ wrote on 2026-03-25, 04:47:
rasz_pl wrote:

Now considering the other fact about your 550mhz Pentium 3 also unable to boot at 100MHz, and this is controlled by CPU pin hard linked directly to clockgen SEL100/66# pin, and it points even stronger at W124G being defective in some strange way.

I think I and maybe others thought OP was able to try and boot at 100, but it sounds like so far the 100fsb option hasn’t even been selected to attempt it

Yeah I haven't even been able to select the option to boot at 100mhz, I'll try pressing on that chip and see what happens, it couldn't hurt to try. I'm still gonna flash the BIOS to the newest version available on the retro web though.

Reply 24 of 31, by bunghole102

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rasz_pl wrote on 2026-03-25, 03:02:
so it locks up the moment you enter the menu, before you even try changing anything? […]
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bunghole102 wrote on 2026-03-24, 15:28:

every time I try to enter that menu the machine locks up on me, and trying to navigate the menu with the keyboard causes strange beeping to come from the PC speaker. Any idea what that's about or how to fix it?

so it locks up the moment you enter the menu, before you even try changing anything?

bunghole102 wrote on 2026-03-24, 15:28:

trying to navigate the menu with the keyboard causes strange beeping to come from the PC speaker. Any idea what that's about or how to fix it?

so its frozen when entering menu/after it draws the new submenu, and pressing keys cases beeping?
Now that is exciting! Sounds like BIOS is unable to communicate with the clockgen chip and hangs because bios author didnt/badly implemented error handling and code is spinning in place.
That beeping is BIOS letting you know keyboard buffer is full and cant take any more key presses, its full because whatever routine supposed to read it and handle keys (the graphical bios menu routine) is busy, its busy because BIOS code handling i2C is busy.

Clockgen is IC Works W124G https://theretroweb.com/chips/4406 (acquired by Cypress Semiconductor in 1999). Communication happens over i2C bus.
Now considering the other fact about your 550mhz Pentium 3 also unable to boot at 100MHz, and this is controlled by CPU pin hard linked directly to clockgen SEL100/66# pin, and it points even stronger at W124G being defective in some strange way.

Im surprised this board works at all 😮 What would be a failure mode of a clockgen chip that makes it ignore two methods of setting clock, but still allow to operate outputting slow FSB and all other corresponding clocks correctly??? The only cosmic coincidence would be unconnected pins 16 and 17 and/or 18.
afaik IC Works W124G is unobtanium. You would have to salvage one from another board. One board I know that uses it is ABit BH6. I even have one for parts 😀

For starters do this experiment:
-turned off computer
-put your finger on W124G, its a chip between PCI slot and battery
-press gently but firmly 😀 keep constant pressure on the chip
-power on computer
-tell us if your Pentium 3 550mhz booted up at 366 or 550 MHz?

If that works then you got lucky and clockgen simply developed some cracked solder joints on pins 16/17/18, resoldering all of its pins will fix the board. If not the board is broken in some other stranger ways.

Okay so I tried pressing down on the chip but nothing changed, it's still booting at 366mhz and not allowing me to change the frequency in the BIOS.

Reply 25 of 31, by bunghole102

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I just flashed the BIOS to the newest revision and that fixed the issue and my Pentium 3 is now presenting at the proper 550mhz 😀 Thanks for the help guys, I can now proceed with the litany of other issues that come with installing Windows 95 and getting it updated 😁

Reply 26 of 31, by rasz_pl

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NeoG_ wrote on 2026-03-25, 04:47:

I think I and maybe others thought OP was able to try and boot at 100, but it sounds like so far the 100fsb option hasn’t even been selected to attempt it

you dont shouldnt have to select this option at all if you insert native 100MHz fsb CPU. BIOS menu is should be for overriding default speed only.

bunghole102 wrote on 2026-03-25, 06:10:

I just flashed the BIOS to the newest revision and that fixed the issue and my Pentium 3 is now presenting at the proper 550mhz 😀 Thanks for the help guys, I can now proceed with the litany of other issues that come with installing Windows 95 and getting it updated 😁

well I stand corrected 😮 wtf is this board even 😀 so it boots a 66 default and then looks up CPUID to set correct fsb? and somehow unknown CPUID makes the bios shit its pants? this is very bad engineering 🙁
now you can try getting 700mhz Pentium 3 running. Which CPU model do you have? Slot1 or on a converter board?

https://github.com/raszpl/sigrok-disk FM/MFM/RLL decoder
https://github.com/raszpl/FIC-486-GAC-2-Cache-Module (AT&T Globalyst)
https://github.com/raszpl/386RC-16 ram board
https://github.com/raszpl/440BX Reference Design adapted to Kicad

Reply 27 of 31, by bunghole102

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rasz_pl wrote on 2026-03-25, 07:08:
you dont shouldnt have to select this option at all if you insert native 100MHz fsb CPU. BIOS menu is should be for overriding d […]
Show full quote
NeoG_ wrote on 2026-03-25, 04:47:

I think I and maybe others thought OP was able to try and boot at 100, but it sounds like so far the 100fsb option hasn’t even been selected to attempt it

you dont shouldnt have to select this option at all if you insert native 100MHz fsb CPU. BIOS menu is should be for overriding default speed only.

bunghole102 wrote on 2026-03-25, 06:10:

I just flashed the BIOS to the newest revision and that fixed the issue and my Pentium 3 is now presenting at the proper 550mhz 😀 Thanks for the help guys, I can now proceed with the litany of other issues that come with installing Windows 95 and getting it updated 😁

well I stand corrected 😮 wtf is this board even 😀 so it boots a 66 default and then looks up CPUID to set correct fsb? and somehow unknown CPUID makes the bios shit its pants? this is very bad engineering 🙁
now you can try getting 700mhz Pentium 3 running. Which CPU model do you have? Slot1 or on a converter board?

It's a slot 1, people earlier in the thread were mentioning how certain motherboards aren't compatible with Coppermine CPUs, do you think the BIOS update would fix that?

Reply 28 of 31, by rasz_pl

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do you have a multimeter to check how its configured right now? alternatively post a picture of your cpu without radiator so we can see which resistors setting Voltage are fitted
https://www.tomshardware.com/reviews/overcloc … ecial,94-6.html
https://bitsundbolts.com/2024/06/06/secc-volt … sing-resistors/

looking at the table masking pins with electrical tape (old school trick from 27 years ago to bump voltage on Celerons) wont work for 1.7 and 1.75 Pentium 3, you would have to solder a small wire. Plus this weird Soyo bios might again not recognize CPU and refuse to set 100MHz bus 😐 so it might also involve Bios modding.

https://github.com/raszpl/sigrok-disk FM/MFM/RLL decoder
https://github.com/raszpl/FIC-486-GAC-2-Cache-Module (AT&T Globalyst)
https://github.com/raszpl/386RC-16 ram board
https://github.com/raszpl/440BX Reference Design adapted to Kicad

Reply 29 of 31, by AlexZ

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It will be easiest for you to buy PIII 900 socket370 and a slotket with voltage jumpers (to request 1.8V). Slotket will probably cost more than the CPU though. You can sell the Slot 1 PIII 700 to recover some of the cost.

rasz would just solder a wire, but unless you have experience with that you shouldn't do it.

Pentium III 900E,ECS P6BXT-A+,384MB,GeForce FX 5600, Voodoo 2,Yamaha SM718
Turion 64 ML-37@2.4Ghz,Gigabyte GA-K8NE,2GB,GeForce GTX 275,Audigy 2ZS
Phenom II X4 955,Gigabyte GA-MA770-UD3,8GB,GeForce GTX 780
Vishera FX-8370,Asus 990FX,32GB,GeForce GTX 980 Ti

Reply 30 of 31, by NeoG_

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Doesn't seem worth it for a win95 machine TBH

98/DOS Rig: BabyAT AladdinV, K6-2+/550, V3 2000, 128MB PC100, 20GB HDD, 128GB SD2IDE, SB Live!, SB16-SCSI, PicoGUS, WP32 McCake, iNFRA CD, ZIP100
XP Rig: Lian Li PC-10 ATX, Gigabyte X38-DQ6, Core2Duo E6850, ATi HD5870, 2GB DDR2, 2TB HDD, X-Fi XtremeGamer

Reply 31 of 31, by bunghole102

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This is a late response but I decided to just go ahead and keep the 550mhz Pentium 3 in the machine, and I have been using it for several days now without any issues.

Thanks for all the replies and help with this!

P.s. I'm probably just gonna sell the 700mhz Pentium 3, I kinda have no use for it now :v