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How do I cool an 84W to 115W CPU system with 92mm case fans? How much CFM?

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computerdude92

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I need help please. Lets take a Pentium 4 HT system for example: In a case that only offers 92mm fans, how much CFM for the fans is needed? Thanks.
 
computerdude92 said:
I need help please. Lets take a Pentium 4 HT system for example: In a case that only offers 92mm fans, how much CFM for the fans is needed? Thanks.
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Know one knows for sure, it's not an exact science. I have a P4 D that runs inherently hot, and no amount of case fans are going to keep it cool. What you can do, if it is a major concern to you, is to get a CPU liquid cooler like a Corsair H100. Or, if you;re not into liquid cooling, which is very good btw, you can go with a standard attachable CPU fan assembly.

Late edit: You'll want your case fans in a push-pull configurations.
 
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If it's a PGA478 system, there aren't many good options due to the weird mounting system Intel used at the time. I'd suggest getting a heatsink from a Optiplex GX270 and one of their heatsink retainers and try and rig something up. I think the hole spacing for the bracket is the same as on normal PGA478 motherboards. This one is designed for a blower that sucks air through the fins, but a normal fan should work as well, just be a bit less efficient.

https://www.ebay.com/itm/175069574938

Zalman did make a good copper cooler, but they're hard to find now and expensive. Here's an example of one, but its in poor condition and missing the crossbars that retain it in the heatsink retention bracket. It could probably be cleaned up and something rigged up to make it work. I have this same cooler and it works pretty good, it's just really fiddly to mount.

https://www.ebay.com/itm/275041805165

If it's an LGA775 system, you have more options. Back when I had a Pentium D system, I used an ASUS V60 and it kept even the smokin' hot 130W variants cool.

https://www.ebay.com/itm/304157259683

Cooler master also has the Hyper TX3 and 212 that works on 775.

https://www.ebay.com/itm/174969017035

https://www.newegg.com/p/N82E16835103099

The Hyper 212 at one time did support LGA775, I don't know if this is true still or not, but the pictures of the retention brackets look the same as the one on my LGA775 rig.
 
478 can be a real problem finding. I wound up with an Ultra X Wind model, but note that the fan is 120 mm--that may be too big for many motherboards--it does work well, however on my Advantech system.
 
You have two issues, one being having a heatsink and cooling fan that can keep the CPU running cool, and having enough air circulating in the case to get rid of that heat and bring cold air in.

Period correct aftermarket cases for P4 CPU had a duct in the side door feeding cool air directly into the CPU fan, and those had 90mm fans cooling the case itself plus whatever GPU you were using (another thing to consider if you have a gaming GPU).
 
So 90mm fan cases were period correct then? So with a proper air cooler, I should be fine? I will not overclock. What amount of CFM for those 90mm fans was common back then? Thanks.
 
I've got a (horizontal) HTPC case for a 478 motherboard that places the vents in the lid right over the CPU. Other systems might use a ducted fan. As far as keeping the case cool, that shouldn't be a problem unless it's a microATX or ITX case. I run 84W Socket 939 CPUs in mini-tower cases with only slight case ventilation--temps don't get above 40C or so.
 
computerdude92 said:
So 90mm fan cases were period correct then? So with a proper air cooler, I should be fine? I will not overclock. What amount of CFM for those 90mm fans was common back then? Thanks.
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I think most case fans were only 80mm back then. At least all of mine were. I had an Athlon XP not P4, so a bit cooler (75W). I used Panaflo low-speed fans (2x intake and 2x exhaust) which were 24 CFM each. IIRC I ended up running them at 7V to quiet them down because I didn't need that much airflow.
 
computerdude92 said:
So 90mm fan cases were period correct then? So with a proper air cooler, I should be fine? I will not overclock. What amount of CFM for those 90mm fans was common back then? Thanks.
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It was a mix of 80, 90 and 92mm. The problem was less the CFM of the fan and more how restrictive the fan mesh was. Many cases had lots of tiny holes, rather than say a traditional wire grille, which severely restricted airflow. It created a ton of resistance, so if you don't have a high CFM fan, it'd pull very little air through the case and more often just recirculate its own exhaust.

I used to just get a cutoff wheel and cut all of the mesh out and leave the mounting holes, then install a traditional wire grille over it. It drastically improved airflow and reduced the annoying buzzing/whining from the fan blades chopping air through the case mesh, sort of like how old air raid sirens worked.

The restrictive grille problem wasn't just on the side door though, all fan mounts back then were usually the same stamped steel holes that severely restricted airflow. Cutting all of these out of the case and installing wire grilles drastically improved ventilation.
 
The hypothetical system would have an 84W Pentium 4. I'd be happy with that, but I was curious about how 115W models would fare with 90mm fans also.
 
As far as case cooling goes, a lot depends on the case design. I like the cases that put a fan at the far end of the expansion card area. You can always use a temperature probe to see how your case is doing and take appropriate action.
 
computerdude92 said:
The hypothetical system would have an 84W Pentium 4. I'd be happy with that, but I was curious about how 115W models would fare with 90mm fans also.
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If you have a heatpipe cooler, the 115W models aren't unmanageable. If you have a bog standard aluminum cooler on the other hand, be prepared for a bad time.
 
On this era, even in the day, ya Zalman flower coolers. Most older socket 939 coolers supported 478 as well. If you do order a Zalman I believe i still have the mounting hardware for 478 on a 7000cu, if you cannot find the bracket. If you arent picky, I have a few on machines I can pull a used random heatsink for you. Im not much a 478 enthusiast.
 
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