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I just bought a firewall that is very loud. The biggest problem is the two fans in the back (2 x Sunon 40mm fans) running at full speed.

The firewall is 1RU with pfSense installed on it.The CPU is a Pentium 4 2.8 GHZ with a heat sink on top.

The air is lead through a plastic tunnel across the unit with the fans in the back and the CPU in the front.

Do i really need two fans running at full speed? Can I reduce it to something like 5v? Will that affect the performance or do I even risk burning the CPU?

Are there any quiet fans I can replace them with?

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Why does it matter? Servers should be in an isolated room with proper cooling and humidity. No one should really be able to hear them. – MDMarra Jan 21 '13 at 3:04
2013. And you buy a firewall with a P4 CPU? SERIOUSLY? THat is end of life. Not as in "out of support" but so old it is likely to fail every day now. Man, where did you find some archeological artifact like that? Why did you buy that in the light of special ahrdware firewalls jus acouple of hundred USD for a LOT more performance? – TomTom Jan 21 '13 at 4:10
It sounds like you made the mistake of buying 1U equipment for a small office where no proper server room is available. (I've been there.) These things are loud, and the only viable solutions would cost more than buying a tower server chassis. – Silver Quettier Feb 26 '13 at 11:04

I don't recommend this. These old Pentium 4's were hot. Very hot. Especially the old 400Mhz FSB processors.

By disabling or lowering those fans, you're probably going to overheat your server.

Swapping them for low-noise fans won't help much either. Low-noise fans work mostly by being huge and turning at a slow RPM. A 1RU server doesn't have much room, so the fans have to be tiny. Because they have to be tiny, they have to spin at a very high RPM in order to move the air required to keep the server cool.

These servers are designed to run in a rack a long way away from people, so they're not designed with noise in mind. Just be glad you don't have one of the newer 1RU servers that often have two rows of 8 fans back-to-back for a total of 16x 40mm fans.

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