case fans speed

danlightbulb

danlightbulb

danlightbulb

Soldato
Joined
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Birmingham
Hi guys.

At what temperature do case fans start to speed up?

Mine are sitting at the same rpm all the time, from a 30 degree idle up to low 60's during stress tests.

The cpu fan is increasing and decreasing in speed all the while.

Thanks
 
It depends on the fans, the method of control and the method connection.

Maybe your fans are directly connected to the PSU or that fan control is not enabled on your motherboard if you are connecting through that.
 
They are 3 pin connected to the motherboard headers.

BIOS seems to be set to vary them based on some proportion of voltage per degree celsius

They are running at mid 800s rpm all the time.
 
use something like speedfan to get full control of them; then you can assign some profiles on how fast you want them to spin at what temps.
 
Tried speedfan, doesn't seem to be able to detect my fans as there are none in the list.

The BIOS allows me to set a PWM value per degree of temperature. The BIOS was set to auto mode.

I have changed it to manual and set the fans to 2.25 PWM value per degree and the rpm's have gone up to the 900's. I'm not sure what the max RPM of the fan is - I'm guessing not as high as the CPU fan which can go to 1500rpm.

The case fans appear quite quiet in comparison (Phanteks case fans came with the case), so I might just set them to max?
 
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Motherboard PWM control and the PWM/degree feature shouldn't translate to 3 pin fans. There should be another setting other than PWM that you can use to get better control over the fans, that is if the motherboard supports 3 pin fans.

There are PWM to DC fan controllers available, using similar concepts to the one I designed and now use, pictured below.
 
As teallc mentioned, there should be a setting for dc fan control in the bios. Gigabyte is renowned for their user-baffling bios. I am using a gigabyte board at the moment and I have it set on the preset option (silent/normal etc..) instead of setting a pwm value per temperature unit
 
My Gigabyte board (a few years old though) has no DC fan control options. I did manage to get speed fan working though despite this, although it was quite a fiddle. In the end I just embraced PWM control via a converter to 3 pin and it works perfectly.

Maybe your board has limited DC fan control options like mine. Check your manual. Each fan header will have a description of the function of each pin. If pin 2 says Fan control then DC will work to some degree.
 
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It works on the cpu fan which ive seen go from 600s to 1500 rpm. The case fans hover mid 800s rpm all of the time. All fans are 3 pin in my system. I set the case fans to full speed at they went up to high 900s thats it.

Looking at the mobo manual the pins on the cpu fan are different to the sys fan headers.

Cpu fan is gnd, 12v, sense, speed control
Sys fans are gnd, speed control, sense, vcc
 
danlightbulb said:
Cpu fan is gnd, 12v, sense, speed control
Sys fans are gnd, speed control, sense, vcc
Click to expand...

That suggests your Sys fans are controllable by voltage rather than just PWM.

I suggest following a guide on Speedfan on how to setup fans. It isn't a particularly intuitive piece of software but should work for those fans, if set correctly.
 
Can't seem to get any fans to show in speedfan. Have selected all the chips in the advanced tab, and there are temperature readings but no fans. Will try the gigabyte tool.
 
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Ive tried the Gigabyte tool and its quite cool! All my fans are there and I can configure a profile.

So next question is what should I be trying to achieve in setting up profiles for my fans?

At the moment I have set the same profiles for the CPU fan and the two case fans. Bearing in mind my ambient temperature in the house today is 27c, my cpu idle temps are around 31c to 35c and the temperature reported as the 'system temp' is 40c.

This profile has all fans running at 40% currently, which is around 650rpm on all fans, give or take.

2ywfy84.jpg
 
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Stealthploit said:
well u can change that in the bios settings i would like it to at full speed at the 60* mark before it actually gets hot not after
Click to expand...

I cant find anything in the bios that lets me define a fan profile. I would have prefered to do it in bios rather than running external software. All my bios allows is four settings per fan: silent, normal ( auto), max, and pwm value per degree.
 
Tealc said:
Motherboard PWM control and the PWM/degree feature shouldn't translate to 3 pin fans.
Click to expand...
It does on at least some Gigabyte Z170 motherboards. The fan headers are clearly auto-switching between 3-pin and 4-pin driving modes depending on the fans attached to them. I've checked all available modes with both 3-pin and 4-pin fans, and they all work the same with both fan types.

There is no mention of this in the manual for the Z170-Gaming K3, but it's definitely doing it with no need for user intervention. Even the CPU_OPT header does it which came as a bit of a surprise as I expected this to be strictly 4-pin only.
 
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So am I best leaving it all on auto in the BIOS then, and not bothering with fan profiles in windows? Its a nice tool to play with but I don't know if what I'm doing has any benefit whatsoever.

15300hz.jpg

250qo46.jpg
 
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