Later CPUs redefined 1.5x as 3.5x, try jumpering as 1.5x

Yes try the 1.5X mutliplier.
https://www.ultimateretro.net/en/motherboards/1118 is a better page than stasons...

I had one of those and I ran it with a K6-2 450 @ 400 MHz for a while (6x66). But I was playing a game one hot summer night, and I heard a pop and it died. I think the voltage regulator for the CPU overheated and died.

Post a clear pic of the clock gen. You may be able to do more than 66mhz bus.

Yes, try 1.5x for the multiplier. The pentium 233 re mapped 1.5 to 3.5

If the board only lists support up to 200MHz, it may not even be able to handle split rail CPUs.
Some people here say it's not a big deal to run PMMX at 3.3-3.5V core voltage. Personally I wouldn't do it.

Anonymous Coward wrote on 2021-11-14, 05:22:

If the board only lists support up to 200MHz, it may not even be able to handle split rail CPUs.
Some people here say it's not a big deal to run PMMX at 3.3-3.5V core voltage. Personally I wouldn't do it.

Could get a powerleap interposer and a k6 3 or k6 3+

Yeah, I’d never put a split rail cpu in a single rais configuration. Risky

Both links up there list jumper settings for 2.6 V and 2.9 V, as well as CPU type selection jumpers with settings for P55C (Pentium MMX). So it obviously supports them.

Now I see it way down at the very bottom. Perhaps I got distracted because of all the stupid ads. Stason sucks. Stop using it. There are plenty of other TH99 mirrors, almost all of them are better.

frudi wrote on 2021-11-14, 08:54:

Both links up there list jumper settings for 2.6 V and 2.9 V, as well as CPU type selection jumpers with settings for P55C (Pentium MMX). So it obviously supports them.

at whom it may interest:
Most socket 7 boards have lower voltage settings if you put in a high boltage voltage chip and play around with a volt meter to the large tab on one of the mosfets and ground

Usually all jumpers removed is the lowest

Unfortunately my 233mhz processor fell to the ground, and I didn't notice, I ended up running over my computer chair, the pins are all smashed 🙁

I ordered another processor, as soon as it arrives, I will do the test

I have a 166mhz mmx, it was quite popular with overclockers, maybe I play with it a bit, but I really wanted to use the 233mhz to avoid overheating in a baby AT case with poor ventilation

Rikintosh wrote on 2021-11-14, 23:22:

Unfortunately my 233mhz processor fell to the ground, and I didn't notice, I ended up running over my computer chair, the pins are all smashed 🙁

I ordered another processor, as soon as it arrives, I will do the test

I have a 166mhz mmx, it was quite popular with overclockers, maybe I play with it a bit, but I really wanted to use the 233mhz to avoid overheating in a baby AT case with poor ventilation

😳😱🤢🤮

Well, may as well order a k6 2+ 570 they are on ebay.

Sphere478 wrote on 2021-11-14, 23:44:

Rikintosh wrote on 2021-11-14, 23:22:

Unfortunately my 233mhz processor fell to the ground, and I didn't notice, I ended up running over my computer chair, the pins are all smashed 🙁

I ordered another processor, as soon as it arrives, I will do the test

I have a 166mhz mmx, it was quite popular with overclockers, maybe I play with it a bit, but I really wanted to use the 233mhz to avoid overheating in a baby AT case with poor ventilation

😳😱🤢🤮

Well, may as well order a k6 2+ 570 they are on ebay.

I already have an AMD k6 build, it even has an AGP slot, I want to build an intel MMX because the case already has one of those metal stickers written intel mmx

Sphere478 wrote on 2021-11-14, 23:44:

Rikintosh wrote on 2021-11-14, 23:22:

Unfortunately my 233mhz processor fell to the ground, and I didn't notice, I ended up running over my computer chair, the pins are all smashed 🙁

I ordered another processor, as soon as it arrives, I will do the test

I have a 166mhz mmx, it was quite popular with overclockers, maybe I play with it a bit, but I really wanted to use the 233mhz to avoid overheating in a baby AT case with poor ventilation

😳😱🤢🤮

Well, may as well order a k6 2+ 570 they are on ebay.

I'd be cautious running anything that draws more power current than a P1MMX in this board. The VRM is essentially just two LDOs and they will struggle.
See

Repo Man11 wrote on 2021-11-14, 04:10:

I had one of those and I ran it with a K6-2 450 @ 400 MHz for a while (6x66). But I was playing a game one hot summer night, and I heard a pop and it died. I think the voltage regulator for the CPU overheated and died.

Doornkaat wrote on 2021-11-15, 00:56:

I'd be cautious running anything that draws more power than a P1MMX in this board. The VRM is essentially just two LDOs and they […]
Show full quote

Sphere478 wrote on 2021-11-14, 23:44:

Rikintosh wrote on 2021-11-14, 23:22:

Unfortunately my 233mhz processor fell to the ground, and I didn't notice, I ended up running over my computer chair, the pins are all smashed 🙁

I ordered another processor, as soon as it arrives, I will do the test

I have a 166mhz mmx, it was quite popular with overclockers, maybe I play with it a bit, but I really wanted to use the 233mhz to avoid overheating in a baby AT case with poor ventilation

😳😱🤢🤮

Well, may as well order a k6 2+ 570 they are on ebay.

I'd be cautious running anything that draws more power than a P1MMX in this board. The VRM is essentially just two LDOs and they will struggle.
See

Repo Man11 wrote on 2021-11-14, 04:10:

I had one of those and I ran it with a K6-2 450 @ 400 MHz for a while (6x66). But I was playing a game one hot summer night, and I heard a pop and it died. I think the voltage regulator for the CPU overheated and died.

K6 + cpus use very little power. So little you can passively cool them sometimes.

Sphere478 wrote on 2021-11-14, 19:46:

at whom it may interest: Most socket 7 boards have lower voltage settings if you put in a high boltage voltage chip and play aro […]
Show full quote

frudi wrote on 2021-11-14, 08:54:

Both links up there list jumper settings for 2.6 V and 2.9 V, as well as CPU type selection jumpers with settings for P55C (Pentium MMX). So it obviously supports them.

at whom it may interest:
Most socket 7 boards have lower voltage settings if you put in a high boltage voltage chip and play around with a volt meter to the large tab on one of the mosfets and ground

Usually all jumpers removed is the lowest

Many boards aren’t dual plane and lack the second regulator

Fun hack is to mod your socket 5 VIO itself for 2.9-3.1 volts and then your PMMX shouldn’t flame up if the board remains stable.

rmay635703 wrote on 2021-11-15, 02:09:

Sphere478 wrote on 2021-11-14, 19:46:

at whom it may interest: Most socket 7 boards have lower voltage settings if you put in a high boltage voltage chip and play aro […]
Show full quote

frudi wrote on 2021-11-14, 08:54:

Both links up there list jumper settings for 2.6 V and 2.9 V, as well as CPU type selection jumpers with settings for P55C (Pentium MMX). So it obviously supports them.

at whom it may interest:
Most socket 7 boards have lower voltage settings if you put in a high boltage voltage chip and play around with a volt meter to the large tab on one of the mosfets and ground

Usually all jumpers removed is the lowest

Many boards aren’t dual plane and lack the second regulator

Fun hack is to mod your socket 5 VIO itself for 2.9-3.1 volts and then your PMMX shouldn’t flame up if the board remains stable.

Yeah there is a little bit of a grey area between socket 7 and 5 🤣. I mean true dual voltage socket 7 boards.

The TX chipset MB8500TTD has the same issue, so Feipoa added a small fan to cool the VRM when running a K6-2+. Re: mb-8500ttd manual needed

I noticed that the vrm heatsinks didn't have thermal compound of any kind, so I took the heatsinks apart and added some generic thermal compound, I think this did good.

I believe that VRM doesn't need a fan if the CPU cooler is blowing air to the sides. In the case of Feipoa, I think the VRMs were overheating because a heatsink with horizontal fins was used, which prevented the air blown by the fan from reaching the VRM's heatsinks. Although a fan is always good, the downside is noise and one more part that will wear out over time.

Repo Man11 wrote on 2021-11-15, 04:17:

The TX chipset MB8500TTD has the same issue, so Feipoa added a small fan to cool the VRM when running a K6-2+. Re: mb-8500ttd manual needed

Are you saying that the lower voltage makes the regulators hotter despite the k6 + processors themselves using less watts than other processor types?

🤔 makes sense, higher the voltage difference between input and output the more conversion heat is produced. I see this on my solar controllers. But that’s a difference of nearly 100v didn’t think a 1v difference would be that bad.