Balancing intake and exhaust case fans speeds (and stuff)

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izumi
Posts: 4
Joined: Sun May 22, 2011 4:40 am

Balancing intake and exhaust case fans speeds (and stuff)

Post by izumi » Sun May 22, 2011 5:07 am

Hello everyone! About a week ago my PSU (Corsair HX520W by the way) blowed and I decided not only to replace it, but make my whole setup more cool and more quiet. That was a crazy week and now I know a lot about fans and their adjustment, and reading this forum helped a lot.

But there are a few questions left, which I'd like to clear up if possible.

First question is - I have two case fans: "Scythe Slip Stream 120mm 1,200rpm" as front intake fan and "Scythe Slip Stream 120mm 1,200rpm" as rear exhaust fan. When they both run on full speed, front fan is very noisy while rear fan is quiet. I figured that it's because front fan is obstructed by front panel of my case and lowered its speed by 800rpm using SpeedFan. So now I have front intake fan running 800rpm and rear exhaust fan running 1200 rpm. Is this balance normal or should I replace rear exhaust fan with 800rpm version so they both run 800 rpm?

Second question is - I tried to control rear exhaust fan using SpeedFan, but I guess sys_fan2 socket on my Gigabyte GA-MA770T-UD3P motherboard can't be controlled. Am I right or there is a way to control it?

And third question - I replaced stock fan on my Cooler Master GeminII S cpu fan with Cooler Master Excalibur fan, and Excalibur makes nasty whistling noise while running about 1000 rpm. Is it okay for this cpu fan if I just fix its speed on 800rpm? My cpu is AMD Phenom II X2 550.

I apologize for a ton of questions in one post, but I figured that making three topics at the same time wouldn't be nice :)

izumi
Posts: 4
Joined: Sun May 22, 2011 4:40 am

Re: Balancing intake and exhaust case fans speeds (and stuff

Post by izumi » Tue May 24, 2011 12:31 am

I figured that there is no way to control sys_fan2 and set variable speed for cpu fan (800-1400 rpm). The only question is about balancing speeds now.

kuzzia
Friend of SPCR
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Joined: Fri Jul 02, 2010 4:41 am
Location: Denmark

Re: Balancing intake and exhaust case fans speeds (and stuff

Post by kuzzia » Tue May 24, 2011 3:07 am

A little under pressure inside a case is not a problem. In fact, I've always believed in low air pressure over high air pressure inside the case.

Many Antec cases only ship with exhaust fans. So the "lack of balance" is by no means harmful. And unless your system has weird thermal characteristic you can just leave your fans "off balance" .

izumi
Posts: 4
Joined: Sun May 22, 2011 4:40 am

Re: Balancing intake and exhaust case fans speeds (and stuff

Post by izumi » Tue May 24, 2011 5:11 am

Thanks! I'll leave it like this then.

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