Be Quiet! CPU Fan not running above ~1500 RPM - CPU gets hot.

casanova02 · Nov 19, 2016

Hey. Not sure if I'm the right place to post this, but here's my problem: Lately I've been a little curious about my PC Temps and I noticed my CPU (i5 2500k) gets really hot (like 45-50ºC) idling. I game a lot and I play graphically intensive games on it (GTA V for example) and I hadn't noticed the CPU gets 70-80ºC easily. I downloaded SpeedFan and changing the CPU Fan Speed does nothing. (0% or 100% just doesn't do anything, Fan keeps going at ~1500 RPM). I also went on the BIOS and changed all those settings for Turbo Fan mode, Manual Mode and put 100% all the time, disabled and enable CPU Q-Fan Control and nothing. Max the fan spins is 1500ish RPM. It's a Be Quiet! Dark Rock (Pro?) 3 fan I've had since I built my Gaming PC back in 2012 and I hadn't noticed any of this until now that I was thinking about overclocking my CPU so it can keep a bit better with the freshly installed RX 480. Also, I remember some time ago getting the error "CPU Fan Error" when starting the machine up, but ended up disabling some option to ignore it, didn't think it was important since the fan was spinning. Should I be worried? Is the cooler broken and should I replace it? If so, alternatives? Should I keep gaming on it?
Thanks in advance!

synphul · Nov 20, 2016

There's not really much on an air cooler to be broken. Not unless there's a manufacturing defect with nothing inside the vapor chambers of the heat pipes, bent/deformed heat pipes etc. The fans either work or don't work. It sounds like something in the bios settings for fan speed control, many bios have a fan speed curve set to increase fan speed at various temps. For example 30% fan speed at temps under 50c, 50% fan speed at temps between 50c and 65c and 100% speed at temps over 65c. That's an over simplification of it but that's the idea. It's possible the fan speeds need adjusted there.

I've not had much luck with speedfan personally. It reads and controls my gpu fan but can't see my cpu fan and has no control over it. I'm using the same cooler. Where were you getting the cpu fan error, was it a windows system message, a warning within speedfan or? I'd suggest trying a program like realtemp to monitor cpu temps and see if in fact the cpu is running that hot or if it's read improperly by speedfan.

The inner 135mm fan spins up to 1400rpm, the front 120mm fan spins up to 1700rpm. If you adjusted the fan in the bios and set it to max you should be able to hear a difference between the fans running at full or partial speed. At partial speed they're nearly silent, at full speed they should be audible. If the fan error is a system warning maybe there's a problem with the cpu_fan header/control via the motherboard. What board is it, brand/model?

The cooler itself is a pretty solid cooler, I wouldn't get rid of it just yet. Something else is going on if you're hitting 70-80c on the cpu while gaming unless you're running an insane overclock on your cpu. My 4690k is oc'd to 4.6ghz and while gaming it hovers around 60c with ambient room temps of around 72-75f.

Have you cleaned the cooler out by chance? If not make sure to give it a good dusting with compressed air or electronics vacuum. It may have dust accumulated and reducing the cooling efficiency. If possible try using a flashlight and while the cooler is powered shine the light over the top of the cooler or from the front side. The inner fan shroud is slightly higher than the cooling fins so if you shine the light in there you will be able to see if it's spinning or not. If it got full of dust over the years it may have stopped that center fan causing a partial air blockage in the middle of the cooler that you can't easily see. The front fan may be spinning while the middle fan isn't.

casanova02 · Nov 20, 2016

synphul :

There's not really much on an air cooler to be broken. Not unless there's a manufacturing defect with nothing inside the vapor chambers of the heat pipes, bent/deformed heat pipes etc. The fans either work or don't work. It sounds like something in the bios settings for fan speed control, many bios have a fan speed curve set to increase fan speed at various temps. For example 30% fan speed at temps under 50c, 50% fan speed at temps between 50c and 65c and 100% speed at temps over 65c. That's an over simplification of it but that's the idea. It's possible the fan speeds need adjusted there.

I've not had much luck with speedfan personally. It reads and controls my gpu fan but can't see my cpu fan and has no control over it. I'm using the same cooler. Where were you getting the cpu fan error, was it a windows system message, a warning within speedfan or? I'd suggest trying a program like realtemp to monitor cpu temps and see if in fact the cpu is running that hot or if it's read improperly by speedfan.

The inner 135mm fan spins up to 1400rpm, the front 120mm fan spins up to 1700rpm. If you adjusted the fan in the bios and set it to max you should be able to hear a difference between the fans running at full or partial speed. At partial speed they're nearly silent, at full speed they should be audible. If the fan error is a system warning maybe there's a problem with the cpu_fan header/control via the motherboard. What board is it, brand/model?

The cooler itself is a pretty solid cooler, I wouldn't get rid of it just yet. Something else is going on if you're hitting 70-80c on the cpu while gaming unless you're running an insane overclock on your cpu. My 4690k is oc'd to 4.6ghz and while gaming it hovers around 60c with ambient room temps of around 72-75f.

Have you cleaned the cooler out by chance? If not make sure to give it a good dusting with compressed air or electronics vacuum. It may have dust accumulated and reducing the cooling efficiency. If possible try using a flashlight and while the cooler is powered shine the light over the top of the cooler or from the front side. The inner fan shroud is slightly higher than the cooling fins so if you shine the light in there you will be able to see if it's spinning or not. If it got full of dust over the years it may have stopped that center fan causing a partial air blockage in the middle of the cooler that you can't easily see. The front fan may be spinning while the middle fan isn't.

Thanks for the detailed answer. The motherboard is an Asus P8Z68-V LE. Thermal paste has been changed recently too so I think that's not the issue.

Today I proceeded to update my BIOS. Now my cooler keeps 600-700 RPM while idling and the same 1500 RPM when the CPU is being stressed. (I'm using Prime95). And my temps keep 39-43ºC idle , 60ºC-75ºC under stress. No overclock.

No idea what it can be.. Like I said, putting it into 100% in BIOS doesn't change anything.

synphul · Nov 20, 2016

Did you have trouble mounting the cooler? It's pretty large, when I installed mine I did it with the board out of the case.

A tip for making cooler installation easier and to help make sure it's mounted flat (rather than tilted/crooked) on the cpu is to place the cooler face down on a table with the cooling plate facing up. Apply the paste to the cpu while it's locked down in the motherboard socket along with the ram installed (can't access after the cooler is mounted) and to lower the motherboard upside down onto the cooler. Essentially mounting the motherboard to the cooler rather than the other way around. That way it simplifies trying to support the weight of the cooler in your hand and trying to get it straight while tightening it down.

You said it makes no difference when setting your cpu fan to 100% speed in the bios. Can you hear the cpu fans with the side panel removed? You may have to put your ear somewhat close to the case but if they're truly running 100% you should be able to hear them.

Another option you might try is unplugging the cooler fans from the cpu_fan header and attaching the cooler fan instead to another header like cha_fan. It will likely give a cpu fan error message with the cooler attached elsewhere (it's looking for signal on the cpu_fan header) but if the cooler fans spin up faster it may be an issue with the motherboard's cpu_fan header itself. The bios should be able to control the fan speed and if it's ineffective it sounds like a faulty motherboard.

Mikel_4 · Dec 2, 2016

The problem is you're going to use your creative intuition to replace the PRO's fan with non standard dark rock fan, kinda hard to find the original dark rock fan or maybe you should contact be quite to ask for replacement with discount.
The PRO has two fans, the non PRO only one fan. so you can try use 120 mm fan to replace 135 mm silent wing, my pick is corsair ML 120 for the non PRO, and corsair ML 120 + any slim 120 mm fan for PRO

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Be Quiet! CPU Fan not running above ~1500 RPM - CPU gets hot.

casanova02

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Mikel_4

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