VOGONS


First post, by 4dam

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Hi, I decided to change My Pentium 120 to Pentium 200MMX and the MMX CPU have 3.3V but should have 2.8V.
My Motherboard is Intel Advanced/ML. Can I change voltage to 2.8V?
Second question, is 40mm fan with stock P120 Radiator will be enough for this higher voltage? I thinking about something from Socket 370 cooling, it seems to be compatible.

Last edited by 4dam on 2019-01-05, 12:04. Edited 2 times in total.

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Reply 3 of 17, by 4dam

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I don't want to overclock it, 200mhz is more than enough for my build.
It's working on 200mhz without problem but is getting hot after ~20 min. I'm not want to overheat it after I get proper cooling and I've only tested jumper settings and overall stability in windows. The voltage has been checked in AIDA and it's 3.3V.

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Reply 4 of 17, by The Serpent Rider

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I think tall socket 7 cooler should be enough. Socket 370 box coolers from Intel should be pretty much the same.

I must be some kind of standard: the anonymous gangbanger of the 21st century.

Reply 6 of 17, by The Serpent Rider

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No, internal sensors started from PII Deschutes. Some Socket 7 boards had external sensor under socket though.

I must be some kind of standard: the anonymous gangbanger of the 21st century.

Reply 7 of 17, by gdjacobs

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You could try to find an interposer, although they're rare and expensive these days.

All hail the Great Capacitor Brand Finder

Reply 9 of 17, by Skyscraper

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I personally wouldn't bother with any modifications.

A heatsink with fan on the CPU (use thermal paste) and at least some airflow over the motherboard near the voltage regulator and everything usually will be just fine. A Pentium MMX is next to impossible to kill and as long as the voltage regulator isn't running ridiculously hot there should be no issues with running the CPU overvolted at 3.3V.

At 300+ MHz and 3.5V things are a bit different and good cooling of both the CPU and motherboard is needed. The absolute max voltage (as in don't ever go above even short term) for the Pentium MMX is quoted as 3.7V.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 10 of 17, by jesolo

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Skyscraper wrote:

At 300+ MHz and 3.5V things are a bit different and good cooling of both the CPU and motherboard is needed. The absolute max voltage (as in don't ever go above even short term) for the Pentium MMX is quoted as 3.7V.

Not sure where you got your information from. You aren't perhaps referring to the standard Pentium 200 MHz (P54CS)?

All MMX CPU's (P55C) are dual voltage with a recommend vcore of 2.8V (max 2.9V) and a secondary (I/O) core of 3.3V (refer https://ark.intel.com/products/49966/Intel-Pe … -MHz-66-MHz-FSB).

Personally, I wouldn't recommend going over the manufacturer specifications, especially if you wish to prolong the life of your CPU and considering that these CPU's are now more than 20 years old.

Reply 11 of 17, by Skyscraper

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jesolo wrote:
Not sure where you got your information from. You aren't perhaps referring to the standard Pentium 200 MHz (P54CS)? All MMX CP […]
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Skyscraper wrote:

At 300+ MHz and 3.5V things are a bit different and good cooling of both the CPU and motherboard is needed. The absolute max voltage (as in don't ever go above even short term) for the Pentium MMX is quoted as 3.7V.

Not sure where you got your information from. You aren't perhaps referring to the standard Pentium 200 MHz (P54CS)?

All MMX CPU's (P55C) are dual voltage with a recommend vcore of 2.8V (max 2.9V) and a secondary (I/O) core of 3.3V (refer https://ark.intel.com/products/49966/Intel-Pe … -MHz-66-MHz-FSB).

Personally, I wouldn't recommend going over the manufacturer specifications, especially if you wish to prolong the life of your CPU and considering that these CPU's are now more than 20 years old.

I know... thats why I wrote "overvolted at 3.3V". I do know my CPUs and their stock voltages I promise! 😜

The absolute max core voltage (as in never ever go over) at 3.7V is from Intels own specifications for the Pentium MMX.

I would not go over 3.3V for every day use without really good cooling (both CPU and motherboard) but I have benched my best Pentium MMX at 350 MHz 3.5V using air cooling. The absolute max voltage in Intels specifications is the voltage where if going above Intel have found in their own testing that it's very likely that the CPU will get damaged fast. It's not the same as saying that voltages below the absolute max voltage always are safe, having some margin to the absolute max is common sense.

I own scores of both CPUs and motherboards so for me the world would not end if a managed to kill a board or a CPU. If the system in question is a very dear system with an impossible to replace unique motherboard then perhaps the owner should invest in a Pentium MMX Overdrive as they are not very expensive.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 12 of 17, by 4dam

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I've bought Cooler Master CMDP5-6I31D-A1

https://i.ebayimg.com/images/g/BwgAAOSweUlbOd2e/s-l225.jpg

with good quality thermal paste.

When cooler will come, I'll try to test how CPU behaves on large load with this overkill heatsink.
I have idea to use multi-meter with the temperature probe to check temperature near to CPU core.
Wish me luck!

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Reply 13 of 17, by Skyscraper

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4dam wrote:
I've bought Cooler Master CMDP5-6I31D-A1 […]
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I've bought Cooler Master CMDP5-6I31D-A1

https://i.ebayimg.com/images/g/BwgAAOSweUlbOd2e/s-l225.jpg

with good quality thermal paste.

When cooler will come, I'll try to test how CPU behaves on large load with this overkill heatsink.
I have idea to use multi-meter with the temperature probe to check temperature near to CPU core.
Wish me luck!

With a large heatsink with fan the CPU will probably stay luke-warm even under prolonged heavy load.

From the picture I found the Intel Advanced/ML seems to have a decent heat sink on the voltage regulator, you can test with the temperature probe to see how hot it gets. If the voltage regulator heat sink gets warmer than lets say 80C during heavy load then increasing air flow is a good idea.

I found a strange thing in the manual though but it's probably a typo.

In the jumper table VRE and OVD are listed, VRE is the defualt. The issue is that VRE is often 3.5V and thats a bit high for comfort.

voltage settings 1.jpg
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On the next page where the jumper settings are explained in more detail only VR and OVD are mentioned and VR is the default. "VR" is normally 3.3V which is what the defult voltage usually is on a Socket 5/7 motherboard so I think that "VRE" in the jumper table is a typo.

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New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 14 of 17, by 4dam

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Skyscraper wrote:

On the next page where the jumper settings are explained in more detail only VR and OVD are mentioned and VR is the default. "VR" is normally 3.3V which is what the defult voltage usually is on a Socket 5/7 motherboard so I think that "VRE" in the jumper table is a typo.

voltage settings 2.jpg

Am I understand correctly, that you suggesting change VRE to OVD settings ? Is that not put up voltage to higher level ?

edit:// this line about "blocking" is intriguing for me, blocking change, change to higher or lower? 😕

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Reply 15 of 17, by Skyscraper

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4dam wrote:
Skyscraper wrote:

On the next page where the jumper settings are explained in more detail only VR and OVD are mentioned and VR is the default. "VR" is normally 3.3V which is what the defult voltage usually is on a Socket 5/7 motherboard so I think that "VRE" in the jumper table is a typo.

voltage settings 2.jpg

Am I understand correctly, that you suggesting change VRE to OVD settings ? Is that not put up voltage to higher level ?

edit:// this line about "blocking" is intriguing for me, blocking change, change to higher or lower? 😕

No I suggest that you use the default setting (pin 4-5). I think Intel made an error when they called the pin 4-5 setting VRE in the jumper table as they corrctly calls it "VR = 3.3V" on the next page (second image).

"Jumper block" is what the "block of jumpers" is called, not because they block something (which they often do) but because they are a block (group) of jumpers.

Last edited by Skyscraper on 2019-01-05, 19:54. Edited 1 time in total.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 16 of 17, by 4dam

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The processor was at start on the 4-5 default pin. Then no chance to change the voltage to lower on this motherboard. Waiting for the cooling then. 😜

Skyscraper wrote:

"Jumper block" is what the "block of jumpers" is called, not because they block something (which they often do) but because they are a block of jumpers.

Yeah, in that context you are right! 😊

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Reply 17 of 17, by 4dam

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Hi!
Remember my problems with voltage? I have Cooler Master for socket 370 and somehow I've mounted it with AC MXII thermal paste on My Pentium 200 MMX.
Working perfectly fine, like 26°C in idle (checked with multimeter). Now I'm waiting for a case to my dream build.
Stay tuned and thanks for your help guys! 😀

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