TheMysteriousGray wrote on 2025-09-16, 02:53:

Understandable. If all else fails, I saw a decent deal for a Socket 370 motherboard on eBay that 100% supports Coppermines, for cheaper than any of the voltage-regulating slotkets I saw. If BIOS flashing doesn't work, I'll bite after I get paid this Friday.

I think that's a pretty great idea if you're not attached to Slot 1 or 440BX and want a fast Coppermine with stability. Which motherboard is it? If you keep looking you might be able to get a good deal on a combo with CPU and PC133 sticks, that way you don't have to potentially pay more for a cooler and everything else separately just to make the switch.

As for the BIOS, it's mostly just my curiosity wanting to see if it'll change anything that could give some better clue as to what's happening. But even if you were to get it to POST and even if the board decided it's okay with 1.8V, at the end of the day it's still 133fsb on a first revision 440BX board with original caps I'm assuming? So I feel like it would only be an exercise in frustration more than something to enjoy...

Also, the BH6 is still a great board for the Katmai. I wouldn't get rid of it or anything, keep it for dedicated DOS gaming since it has ISA slots.

I don't think you mentioned what Slotket you are using.

Show pics with both cpus next to it.

Coppermine were not the same pinout.

myne wrote on 2025-09-16, 06:05:

I don't think you mentioned what Slotket you are using....

TheMysteriousGray wrote on 2025-09-15, 16:07:

I don’t have any slotkets ATM, only two native Slot 1 PIIIs. If it will help tho, I can take photos of both when I get home from work.

Ahhhhh
Right. Go with the bios update.

If it is voltage, as in the cpu itself says 1.7v, changing to 1.8 should be possible by blocking vid1 with sticky tape or nail varnish

1.9 by blocking vid2, 2v by blocking vid 1 & 2

https://www.mouser.com/catalog/specsheets/int … on_24445209.pdf

sunkindly wrote on 2025-09-16, 04:41:

I think that's a pretty great idea if you're not attached to Slot 1 or 440BX and want a fast Coppermine with stability. Which mo […]
Show full quote

TheMysteriousGray wrote on 2025-09-16, 02:53:

Understandable. If all else fails, I saw a decent deal for a Socket 370 motherboard on eBay that 100% supports Coppermines, for cheaper than any of the voltage-regulating slotkets I saw. If BIOS flashing doesn't work, I'll bite after I get paid this Friday.

I think that's a pretty great idea if you're not attached to Slot 1 or 440BX and want a fast Coppermine with stability. Which motherboard is it? If you keep looking you might be able to get a good deal on a combo with CPU and PC133 sticks, that way you don't have to potentially pay more for a cooler and everything else separately just to make the switch.

As for the BIOS, it's mostly just my curiosity wanting to see if it'll change anything that could give some better clue as to what's happening. But even if you were to get it to POST and even if the board decided it's okay with 1.8V, at the end of the day it's still 133fsb on a first revision 440BX board with original caps I'm assuming? So I feel like it would only be an exercise in frustration more than something to enjoy...

Also, the BH6 is still a great board for the Katmai. I wouldn't get rid of it or anything, keep it for dedicated DOS gaming since it has ISA slots.

It’s an Asus CUBX. Still 440BX, but it seems to natively support Coppermine CPUs and I actually have a Socket 370 PIII 966 sitting in a baggie that I never used. My only sound card is an AWE64 Value so my mobo options are limited to ones with ISA slots, not that I’m complaining considering how tricky it is to get PCI cards to be DOS-compatible.

TheMysteriousGray wrote on 2025-09-16, 12:48:

[...]

It’s an Asus CUBX. Still 440BX, but it seems to natively support Coppermine CPUs and I actually have a Socket 370 PIII 966 sitting in a baggie that I never used. My only sound card is an AWE64 Value so my mobo options are limited to ones with ISA slots, not that I’m complaining considering how tricky it is to get PCI cards to be DOS-compatible.

The "CU" part of the CUBX name is Asus' way of saying they engineered it specifically for Coppermine, so no worries there. The board is a very late i440BX board, so has all the options you'd want for running at 133MHz FSB like 1/4 PCI divider and settings up to and over 133MHz. What you don't get is a guarantee it will actually run at 133MHz and be stable. I had one back in the day with a P3-700E. It wouldn't go over 124MHz FSB (running at 868MHz) and wasn't totally stable there either. I assumed the CPU was limiting, but when I got my hands on a P3-1000EB (and some nice CL2 PC133 DIMMs) it still wouldn't go any faster 🙁 Still, on late rev BX boards that's very much the exception, most will happily go to 133MHz and sometimes quite a bit over that.

If you even suspect you'll be doing something with DOS on a board, definitely go with at least one ISA slot. That said, if you already have a Katmai system with lots of ISA slots, even the last, most demanding DOS games are well covered, so it might be worth looking for something with native 133MHz support even if it doesn't have an ISA slot. Iirc there's an Abit SA6 on Amibay at the moment that would do very nicely and has AC'97 integrated sound. You could then later add a PCI sound card chosen for Win98 features, like an Aureal Vortex 2 or (more boring, but easier to find) an SBLive.

I have a CUBX-L, with an added "3.3V voltage booster", like a full CUBX.
And modded for Tualatin support.
And this is not my favorite board. 😀

If the memory problems can still be solved (REG ECC or sorting through all available fancy RAM with CL2), then 89 MHz on AGP for 440BX is basically unsolvable.
Everyone starts with Tualatin + 440BX because it's "classic". But I'd prefer VIA694T with 4 RAM slots from a decent manufacturer.
PS My CUBX-L holds 133 MHz with any three memory sticks (of those I have). With four - only 124 MHz, and this is very annoying.

shevalier wrote on 2025-09-16, 15:01:

I have a CUBX-L, with an added "3.3V voltage booster", like a full CUBX. And modded for Tualatin support. And this is not my fav […]
Show full quote

I have a CUBX-L, with an added "3.3V voltage booster", like a full CUBX.
And modded for Tualatin support.
And this is not my favorite board. 😀

If the memory problems can still be solved (REG ECC or sorting through all available fancy RAM with CL2), then 89 MHz on AGP for 440BX is basically unsolvable.
Everyone starts with Tualatin + 440BX because it's "classic". But I'd prefer VIA694T with 4 RAM slots from a decent manufacturer.
PS My CUBX-L holds 133 MHz with any three memory sticks (of those I have). With four - only 124 MHz, and this is very annoying.

So I guess the safe bet, if I got this board, would be to either run the 966 CPU underclocked or to get one that runs at 100MHz natively. I don’t think I need an absolute monster CPU (relatively speaking of course), I just need one that’s fast enough to run Deus Ex smoothly on Liberty Island. I hear 700MHz is about the point where the game stops having slowdown issues for the most part, so hitting that number would be satisfactory enough I think. Too high and I doubt I could run some DOS games correctly without either shutting off the cache or using DOSBox.

I flashed to BIOS SS and tried again. Exact same thing happened. Voltage is definitely the issue, so I'm in the market for either a new mobo or a slotket.

Earlier you said the cpu was a slot1, now you're saying you need a Slotket.

Both can't be true.

myne wrote on 2025-09-21, 02:24:

Earlier you said the cpu was a slot1, now you're saying you need a Slotket.

Both can't be true.

I have a spare Socket 370 chip that I could put into a slotket. I don't see any way of using the Slot 1 CPU I was trying to make work without modifying it, and I'm neither skilled nor crazy enough to do that.

Have you considered the possibility that the cpu is faulty?

The cubx was built for coppermines according to other posts.
This strongly implies that the voltage support is inbuilt.

The only change from memory was the voltage controller, usually a 20-40 leg rectangular ic. Look for the datasheets of the 2 obvious ones. One will be the clockgen, the other the vrm.

You'll see that the vrm should be capable of ~1.3-2.8v.

Until it works in another board, I'm assuming the cpu is dead.

You could try washing it. I've never had electronics get worse after a good wash. Many have come good.

myne wrote on 2025-09-21, 04:21:

You'll see that the vrm should be capable of ~1.3-2.8v.

It`s jumper-free motherboard.
To apply the settings, it first needs to start the CPU and execute the BIOS.
And only then set the arbitrary voltage value.

myne wrote on 2025-09-21, 04:21:

Have you considered the possibility that the cpu is faulty? […]
Show full quote

Have you considered the possibility that the cpu is faulty?

The cubx was built for coppermines according to other posts.
This strongly implies that the voltage support is inbuilt.

The only change from memory was the voltage controller, usually a 20-40 leg rectangular ic. Look for the datasheets of the 2 obvious ones. One will be the clockgen, the other the vrm.

You'll see that the vrm should be capable of ~1.3-2.8v.

Until it works in another board, I'm assuming the cpu is dead.

You could try washing it. I've never had electronics get worse after a good wash. Many have come good.

the board is a first revision AB-BH6, not a CUBX. I've heard that the 1.0x BH6 boards don't have a voltage regulator equipped to deal with the lower voltages of Coppermine CPUs. I was considering getting the CUBX to replace this motherboard, but unfortunately somebody scooped the one I was looking at out from under me.

I have considered the possibility that the CPU is busted, but I don't have a second system on hand to know for sure. I feel like if the CPU was well and truly dead, then the computer wouldn't respond at all, but it turns on for a second or two each time I plug it back in. It just shuts itself off immediately afterward and refuses to turn on unless I change CPUs.

I could start by just buying a different CPU online, and if that works, I'd know. Hopefully, finding one will be cheaper than finding a good slotket or replacing the motherboard.

TheMysteriousGray wrote on 2025-09-21, 05:43:

the board is a first revision AB-BH6, not a CUBX. I've heard that the 1.0x BH6 boards don't have a voltage regulator equipped to deal with the lower voltages of Coppermine CPUs. I was considering getting the CUBX to replace this motherboard, but unfortunately somebody scooped the one I was looking at out from under me.

I have considered the possibility that the CPU is busted, but I don't have a second system on hand to know for sure. I feel like if the CPU was well and truly dead, then the computer wouldn't respond at all, but it turns on for a second or two each time I plug it back in. It just shuts itself off immediately afterward and refuses to turn on unless I change CPUs.

I could start by just buying a different CPU online, and if that works, I'd know. Hopefully, finding one will be cheaper than finding a good slotket or replacing the motherboard.

There is something fishy going on with your setup. I have BH6 1.01 with SS BIOS and last time I was using it, I had 800/100 Coppermine installed on it. 133MHz FSB won’t most likely work at least reliably because of the lack of 1/4 PCI divider, but otherwise Coppermine shouldn’t be a problem with earlier revisions.

One option is that the mobo is failing, most likely VRM caps and it needs to be recapped.

CharlieFoxtrot wrote on 2025-09-21, 07:29:

TheMysteriousGray wrote on 2025-09-21, 05:43:

the board is a first revision AB-BH6, not a CUBX. I've heard that the 1.0x BH6 boards don't have a voltage regulator equipped to deal with the lower voltages of Coppermine CPUs. I was considering getting the CUBX to replace this motherboard, but unfortunately somebody scooped the one I was looking at out from under me.

I have considered the possibility that the CPU is busted, but I don't have a second system on hand to know for sure. I feel like if the CPU was well and truly dead, then the computer wouldn't respond at all, but it turns on for a second or two each time I plug it back in. It just shuts itself off immediately afterward and refuses to turn on unless I change CPUs.

I could start by just buying a different CPU online, and if that works, I'd know. Hopefully, finding one will be cheaper than finding a good slotket or replacing the motherboard.

There is something fishy going on with your setup. I have BH6 1.01 with SS BIOS and last time I was using it, I had 800/100 Coppermine installed on it. 133MHz FSB won’t most likely work at least reliably because of the lack of 1/4 PCI divider, but otherwise Coppermine shouldn’t be a problem with earlier revisions.

One option is that the mobo is failing, most likely VRM caps and it needs to be recapped.

Is the PCI divider not determined by software in any way? because the BIOS showed that a 1/4 PCI divider kicks in at 133 MHz even before I flashed it to the SS version. If so, that’s an incredibly stupid oversight for the BIOS to offer a feature the board can’t do.

As for the board itself failing, I doubt it. I’ve never faced any stability or voltage issues while using the PIII 450 it came with, and I can even manually lower the voltage in the BIOS to at least 1.8V while running that CPU and nothing bad happens. I don’t think it’s impossible necessarily, it just doesn’t seem likely when the board hasn’t wigged out or been unstable in any other way for the couple months I’ve had it. Maybe some BH6 1.0x boards are built different (metaphorically speaking 🤣) and can handle Coppermines while others can’t?

You could try going into BIOS with the 450 cpu and check which voltages you are able to select manually - or find the VRM chip and see if it's a Coppermine capable one. My own 1.01 BH6 goes all the way down to 1.30 volts and run fine with a slot1 1000/100.

Maybe try holding "Insert" during boot and see if it boots at 66MHz

TheMysteriousGray wrote on 2025-09-21, 05:43:

the board is a first revision AB-BH6, not a CUBX. I've heard that the 1.0x BH6 boards don't have a voltage regulator equipped to […]
Show full quote

myne wrote on 2025-09-21, 04:21:

Have you considered the possibility that the cpu is faulty? […]
Show full quote

Have you considered the possibility that the cpu is faulty?

The cubx was built for coppermines according to other posts.
This strongly implies that the voltage support is inbuilt.

The only change from memory was the voltage controller, usually a 20-40 leg rectangular ic. Look for the datasheets of the 2 obvious ones. One will be the clockgen, the other the vrm.

You'll see that the vrm should be capable of ~1.3-2.8v.

Until it works in another board, I'm assuming the cpu is dead.

You could try washing it. I've never had electronics get worse after a good wash. Many have come good.

the board is a first revision AB-BH6, not a CUBX. I've heard that the 1.0x BH6 boards don't have a voltage regulator equipped to deal with the lower voltages of Coppermine CPUs. I was considering getting the CUBX to replace this motherboard, but unfortunately somebody scooped the one I was looking at out from under me.

I have considered the possibility that the CPU is busted, but I don't have a second system on hand to know for sure. I feel like if the CPU was well and truly dead, then the computer wouldn't respond at all, but it turns on for a second or two each time I plug it back in. It just shuts itself off immediately afterward and refuses to turn on unless I change CPUs.

I could start by just buying a different CPU online, and if that works, I'd know. Hopefully, finding one will be cheaper than finding a good slotket or replacing the motherboard.

Ah. My bad. Refer back to previous post with datasheet.
1. Identify target voltage.
2. Identify relevant VID pins on slot.
3. Sticky tape to block.
Test.
Any idiot can cut a piece of sticky tape. It is fiddly, but achievable.

H3nrik V! wrote on 2025-09-21, 10:08:

You could try going into BIOS with the 450 cpu and check which voltages you are able to select manually

Once again, this is a jumper-free motherboard.
It sets the voltage specified in the BIOS ONLY after it boots.
If it fundamentally doesn't recognize processors with voltages below 1.8 V, then it won't supply power to the processor AT ALL.
There's nothing to change the voltage with—the processor won't be powered at all.

And how Abit control CPU VRM —digitally or through the GPIO of the MIO chip—these are implementation methods.