Is the exhaust fan necessary?

On my new PC, the component making the most noise is the rear exhaust fan on my case (it is the only exhaust fan in my PC). I tried to disconnect it and watched temperatures in SpeedFan and CPU was usually at about 35 °C, peaking to about 50 °C when the system was under load - this doesn't look too bad.

So I'm considering that I'll leave the exhaust fan disconnected permanently after which the computer is very quiet - the only noise-making components are Arctic Cooling Freezer 7 Pro Rev.2 (CPU fan) and PSU fan (Enermax Pro 82+), both being quiet enough as far as I can tell. (My GPU has a passive cooler.) Also, those two components are moving parts, so they will provide some air flow in the case and, even better, PSU fan sucks the air out of the case, so it kind of is an exhaust fan in itself.

Does anyone run with the exhaust fan disconnected? You don't have to tell me that it's always better to have more air flow than less, I know that, but the noise is also a consideration for me and temperatures around 40 °C should be fine shouldn't they?

(I might also consider getting a quieter case fan, but I'm specifically interested in your opinion on the no exhaust fan scenario.)

Borek Bernard

Posted 2010-03-15T09:38:28.240

Reputation: 11 400

Answers

It is worth checking if your BIOS has options to shut down the PC based on the temperature of the CPU. This means if you do decide to run without the exhaust fan then your PC would shut itself down if things were getting too hot preventing damage to the components.

And in reply to your bracketed comment, I would say it's really worth looking into replacing the case fan. The difference in noise between stock components and third-party replacements costing only a few dollars can be huge. Another option would be a fan speed controller so you can lower the speed of the case fan so that it is much quieter but still provides some air flow.

Dave Webb

Posted 2010-03-15T09:38:28.240

Reputation: 10 126

This is a good article on airflow in a computer case.

CGA

Posted 2010-03-15T09:38:28.240

Reputation: 3 767

Very surprising results. Not too worried about missing my side fan anymore. However, many desks put a PC case in an enclosure with very poor circulation often only allowing the best air flow from the rear. I should install a sleek looking vent in the front of the cabinet door. – IAbstract – 2010-03-15T17:32:38.803

If the PSU fan already seems to provide enough air-flow, the additional case fan can be left off. Even ~~more so as~~ though your graphics card has passive cooling.

It looks like the additional fan is overkill in your case.

If you find that you still need it, try to find vibration-decoupling fan mounts. They help a lot.

brandstaetter

Posted 2010-03-15T09:38:28.240

Reputation: 4 119

4I thought that GPU with passive cooling would actually increase demand for a good air flow. – Borek Bernard – 2010-03-15T10:16:32.537

True; I think, however, that the PSU fan produces enough air-flow (if the case is closed). Yes, my answer was badly written. I'll fix it. – brandstaetter – 2010-03-16T11:13:26.167

The CPU is only one component of several in your case that need to stay cool. What about HD, GPU, Motherboard (North & South Bridge)? I would monitor the temps for those as well. Considering the article on airflow listed in the other post, I would just get a good, quiet rear fan. Heat kills.

churnd

Posted 2010-03-15T09:38:28.240

Reputation: 4 228

From the product-level perspective, if you have a new system, the vendor probably will not provide hardware (repair) support if you have disconnected it.

If you assembled the system yourself, those considerations do not apply.

benc

Posted 2010-03-15T09:38:28.240

Reputation: 1 272

I've assembled this computer myself. – Borek Bernard – 2010-03-15T10:01:10.297

If you have a passive GPU cooler: Yes, you do need the exhaust fan. It not only provides cooling, but directs the flow of air though your case.

I assume you have a bottom-front-to-top-rear-air-flow case and if you remove the exhaust fan the air may no longer flow that way and the PSU fan will make things worse because the negative pressure will be there and the air will flow there instead of to the top. Just get a quieter fan and replace that exhaust fan.

John Li

Posted 2010-03-15T09:38:28.240

Reputation: 1

-1

Instead of disconnecting the rear vent i would rather suggest to replace it for quieter one. It is true that only CPU and GPU needs cooling but the fans on them will only pump hot air if there will be no way out for it.

Andy Bucker

Posted 2010-03-15T09:38:28.240

Reputation: 1

-1

A basic idea for a better cooling system is to have two ways of insertion of air and two ways of exit of the hot air of system. Cool-hit recycle!

That is, if your case has rear-side-front-top entrances, top and rear fans should be exhaust fans of hot air and front-side fans should be insertion of cool fresh air.

If you don't have top fan ability, three-way fans should work just fine as well.

So, I don't think that you need to stop any of the fan either. Your system is in relax mode or full loaded. We need to keep it cool all the time for best results of all time.

Gabriel Gabriel

Posted 2010-03-15T09:38:28.240

Reputation: 1

1You're not naswering the question. The OP says "You don't have to tell me that it's always better to have more air flow than less" – Jan Doggen – 2014-09-09T08:02:52.130