VOGONS


Help cooling down a Pentium 3

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Reply 20 of 39, by rasz_pl

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idan182 wrote on 2022-06-05, 04:55:

When pushing it and on games, CPU can reach even 60-65. and motherboard to 40+
is it normal?

yes and no, P3 733mhz TDP=22W Tjmax=100C
temp is fine, but could be lower

idan182 wrote on 2022-06-05, 04:55:

Can I fit a better 80mm front fan? don't think it makes something.
PSU gets very hot and is built weird with inside fan and not a fan that gets the heat out of it:

it might be getting hot because caps dried out and it has to work extra hard with more losses
or airflow is so bad/blocked it just recirculates hot air into itself

Repo Man11 wrote on 2022-06-05, 06:52:

These Coolermaster Socket 370 coolers are available on Ebay for a decent price ($9.99 US), and would be much better than what you now have.

already mounted cooler is perfectly adequate for P3 733mhz 23W CPU

Reversing PSU fan would only make it fight against CPU fan. Its an old/cheap midi design, but was fine with Slot 1 CPUs. I build a few overclocked Socket A systems back in the day in such cases before learning better, they ran HOT AF and froze in the summer making me do home visits to swap into bigger boxes.

Reply 21 of 39, by Hoping

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Ok, someone may have thought of it, but they will have to explain to me how the heat from the power supply is going to cool the processor, maybe I am blinding myself because I can't understand it, and I have never seen something like this in my life. It may simply be that this power supply is not from that era, we have not seen its label, it may also be that this power supply comes from another equipment with another type of case. There are marks around the screws so....
Reversing the fan will help the cpu fan, because the cpu fan is pushing the air against the cpu cooler and the air is exausting from the sides of the cooler so the psu fan will take the hot air outside the case. Again those are the basics, it's not so dificult to understand, take the hot air outside to keep things cool.

Reply 22 of 39, by Sphere478

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Hoping wrote on 2022-06-05, 12:14:

Ok, someone may have thought of it, but they will have to explain to me how the heat from the power supply is going to cool the processor, maybe I am blinding myself because I can't understand it, and I have never seen something like this in my life. It may simply be that this power supply is not from that era, we have not seen its label, it may also be that this power supply comes from another equipment with another type of case. There are marks around the screws so....
Reversing the fan will help the cpu fan, because the cpu fan is pushing the air against the cpu cooler and the air is exausting from the sides of the cooler so the psu fan will take the hot air outside the case. Again those are the basics, it's not so dificult to understand, take the hot air outside to keep things cool.

As long as the processor is hotter than the air coming out of the psu, a cooling effect will be had.

Obviously it’s not as good as air that didn’t pass through the psu.

This setup is really designed for a “passivly”cooled pentium II cartridge the psu would be blowing right on it.

But this adapted slocket is forcing two air paths together. So yeah, a modern large fan “blow out” psu like I suggested would help. If indeed this psu is blowing in. Also, yeah that stock heatsink is probably fine, but repo and I posted some even better ones

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Reply 23 of 39, by Hoping

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For a CPU with a passive heatsink it would make sense, but remember that for slot processors with a passive heatsink, the heatsink was huge, I've had a PIII700 with a passive heatsink that was almost three times the size of the CPU. It belonged to a Compaq computer.
I can't find any pictures on the internet of that processor and it's a shame, I was so stupid to give it away and it was beautiful and huge. 😀

Reply 24 of 39, by Sphere478

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Hoping wrote on 2022-06-05, 13:27:

For a CPU with a passive heatsink it would make sense, but remember that for slot processors with a passive heatsink, the heatsink was huge, I've had a PIII700 with a passive heatsink that was almost three times the size of the CPU. It belonged to a Compaq computer.
I can't find any pictures on the internet of that processor and it's a shame, I was so stupid to give it away and it was beautiful and huge. 😀

Yep that’s the ones.

Sphere's PCB projects.
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Sphere’s socket 5/7 cpu collection.
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SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
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Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 25 of 39, by devius

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For the record my second PC ever had a Pentium II 266MHz, it was actively cooled and it still had one of those reversed airflow PSUs in a generic ATX case. Even at the time it seemed odd to me, but the thing did work fine for 7 years so, with those types of CPUs it probably wasn't that bad since they did have integrated heatsinks and seem quite sturdy.

Also, the heatsink on Slot CPUs without a fan wasn't always huge. Example:
L_Intel-80522PX266512EC%20%28top%29.jpg

Reply 26 of 39, by Hoping

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I think that's around three times the size of most standard socket 370 coolers, but true, no so big as the one I've had, but my memory must be playing me tricks because in CPU-World the p2-266 has a max TDP of 38,2W and the PIII-700 23,8W.
One thing more, did anybody asked if the CPU heatsink is well mounted and with thermal paste, maybe there's also a problem there.
But, the op is mentioning that the PSU gets very hot so were does that heat goes?
From my experience in the case of PIII cpus temperatures over 50ºC are already on the hot side meaning that maybe there's something wrong, the PIII733 has a TDP of around 25W so doesn't need a big cooler.

Reply 27 of 39, by pentiumspeed

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Turn that front fan around so it blows into the case and have PSU blow the air outwards so all the air go in one path in one direction.

Cheers,

Great Northern aka Canada.

Reply 28 of 39, by AlexZ

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Swap case for one that has a more modern power supply with large bottom fan mounted horizontally above the board. Those cases tend to have space to mount an extra fan just below the power supply to blow hot air out of the case. In this setup you would have two fans near the CPU blowing hot air out. They could run at low rpm and be inaudible. My PIII uses case from Athlon XP as they are so much better.

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Reply 29 of 39, by Tetrium

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Personally I'd also be inclined to put this system in a different case.
That case is more suitable for a Slotted system.

Another reason could be that (it's not visible from the pics) the heatsink may be mounted backwards, which could also cause CPU overheating.

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Reply 30 of 39, by bZbZbZ

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I'm assuming you don't want to replace your case (to one with a dedicated exhaust fan near the CPU), and you don't want to replace your motherboard (to an actual Socket 370 mobo).

In this case, generally the best setup is for the front case fan to be an intake, and for the Power Supply to pull hot air from the CPU area and exhaust it out the back of the PSU (out of the computer).

So the first step would be to find another PSU. You can try a modern unit, where nearly all of them use a large intake fan that would suck hot air away from your CPU and through the PSU eventually out of the back of the computer. But there is a risk that the modern power supply might not supply enough 5V for your CPU (modern systems use almost entirely 12V and modern PSUs are designed to match). You could also try to find an older PSU with a similar airflow direction. There were PSUs around the early 2000's with two fans, one pulling air from the CPU area into the PSU and the other fan exhausting out the back of the PSU (out of the computer). Here's an example photo..

In addition to replacing the PSU, I recommend using the front case fan as an intake fan. You could also consider replacing it with a newer/better one (maybe a suitably sized Noctua, although they're pricey).

Good luck!

Reply 31 of 39, by idan182

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bZbZbZ wrote on 2022-06-06, 02:46:
I'm assuming you don't want to replace your case (to one with a dedicated exhaust fan near the CPU), and you don't want to repla […]
Show full quote

I'm assuming you don't want to replace your case (to one with a dedicated exhaust fan near the CPU), and you don't want to replace your motherboard (to an actual Socket 370 mobo).

In this case, generally the best setup is for the front case fan to be an intake, and for the Power Supply to pull hot air from the CPU area and exhaust it out the back of the PSU (out of the computer).

So the first step would be to find another PSU. You can try a modern unit, where nearly all of them use a large intake fan that would suck hot air away from your CPU and through the PSU eventually out of the back of the computer. But there is a risk that the modern power supply might not supply enough 5V for your CPU (modern systems use almost entirely 12V and modern PSUs are designed to match). You could also try to find an older PSU with a similar airflow direction. There were PSUs around the early 2000's with two fans, one pulling air from the CPU area into the PSU and the other fan exhausting out the back of the PSU (out of the computer). Here's an example photo..

In addition to replacing the PSU, I recommend using the front case fan as an intake fan. You could also consider replacing it with a newer/better one (maybe a suitably sized Noctua, although they're pricey).

Good luck!

I have this Thermaltake TR2-550 PSU:

1.AqpVXbaxrkNj6ixOXXUUz6P-rkfp_KRB.4nT3vQjawrEHG-HcLTjcWllpXHCA8uiP0GKR-uOQXJc

Will that suit this old PC? It has just one 120mm fan that gets hot air from the case to outside.
No outside fan.

It has a "ATX 12V 2.0" sticker but also has +5V DC.

Reply 32 of 39, by Sphere478

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idan182 wrote on 2022-06-06, 12:57:
I have this Thermaltake TR2-550 PSU: […]
Show full quote
bZbZbZ wrote on 2022-06-06, 02:46:
I'm assuming you don't want to replace your case (to one with a dedicated exhaust fan near the CPU), and you don't want to repla […]
Show full quote

I'm assuming you don't want to replace your case (to one with a dedicated exhaust fan near the CPU), and you don't want to replace your motherboard (to an actual Socket 370 mobo).

In this case, generally the best setup is for the front case fan to be an intake, and for the Power Supply to pull hot air from the CPU area and exhaust it out the back of the PSU (out of the computer).

So the first step would be to find another PSU. You can try a modern unit, where nearly all of them use a large intake fan that would suck hot air away from your CPU and through the PSU eventually out of the back of the computer. But there is a risk that the modern power supply might not supply enough 5V for your CPU (modern systems use almost entirely 12V and modern PSUs are designed to match). You could also try to find an older PSU with a similar airflow direction. There were PSUs around the early 2000's with two fans, one pulling air from the CPU area into the PSU and the other fan exhausting out the back of the PSU (out of the computer). Here's an example photo..

In addition to replacing the PSU, I recommend using the front case fan as an intake fan. You could also consider replacing it with a newer/better one (maybe a suitably sized Noctua, although they're pricey).

Good luck!

I have this Thermaltake TR2-550 PSU:

1.AqpVXbaxrkNj6ixOXXUUz6P-rkfp_KRB.4nT3vQjawrEHG-HcLTjcWllpXHCA8uiP0GKR-uOQXJc

Will that suit this old PC? It has just one 120mm fan that gets hot air from the case to outside.
No outside fan.

It has a "ATX 12V 2.0" sticker but also has +5V DC.

Give it a go, see how it does. Also, flip that front fan.

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 33 of 39, by Repo Man11

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When you have the front fan out, be sure to lubricate the bearing. There are many tutorials on YouTube if you've never done it before. https://www.youtube.com/results?search_query= … te+computer+fan

"A lot of times when you first start out on a project you think, This is never going to be finished. But then it is, and you think, Wow, it wasn't even worth it." - Jack Handey

Reply 34 of 39, by idan182

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I've replaced the power supply with the 120mm exhaust fan + switched the front fan which was exhaust and not intake.

Temp dropped from:

Motherboard: 36c to 29c
CPU temp: 45c to 38c
GPU temp: 72c to 63c
Hard Disk temp: 45c to 32c

Hooray

Reply 36 of 39, by Sphere478

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You mean to say you used the psu with the 120mm fan?

Excellent results!

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 37 of 39, by Hoping

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Just one detail that a lot of people forget, and that's another basic rule, cold air is heavier than hot air, so hot air is expelled through the top of the case and cold air is brought in through the bottom of the case.
I don't want to seem heavy or rude, but it's basic. http://fowlerearthscience.weebly.com/earth-sc … e-fall-downward.
It's the way this world works.

Reply 38 of 39, by NostalgicAslinger

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devius wrote on 2022-06-05, 16:37:
For the record my second PC ever had a Pentium II 266MHz, it was actively cooled and it still had one of those reversed airflow […]
Show full quote

For the record my second PC ever had a Pentium II 266MHz, it was actively cooled and it still had one of those reversed airflow PSUs in a generic ATX case. Even at the time it seemed odd to me, but the thing did work fine for 7 years so, with those types of CPUs it probably wasn't that bad since they did have integrated heatsinks and seem quite sturdy.

Also, the heatsink on Slot CPUs without a fan wasn't always huge. Example:
L_Intel-80522PX266512EC%20%28top%29.jpg

SL2HE is the 350 nm Klamath Core, very brave without a fan, 44W max. TDP! There are also PII 266 CPUs with Deschutes core on the market, 24W max. TDP with much less heat output than the first Klamath Core. I would look for a CPU like this. Also less load for the now old voltage converters on the motherboards.

Reply 39 of 39, by devius

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I actually have a SL2HE and it comes with the same heatsink as in the picture from cpu-world. It does have an IBM sticker on it, so whatever IBM PC (PC 300GL maybe?) it was in probably had a case fan blowing air directly at it.