PWM woes

Telecaster

Telecaster

Telecaster

Soldato
Joined
17 Jun 2012
Posts
5,951
Hi guys,

I've never been able to set up PWM fans to work how I want, no matter what settings I change they always seem to have a mind of their own.

I recently set up speedfan which is awesome, unfortunately it only works (ironically) on the two 3 pin fans I have, one on the CPU cooler and the other one a case fan. The other two case fans are 120mm Apaches and speedfan simply won't alter them, likewise if I mess with the BIOS PWM settings nothing seems to change.

I would like to link the two Apaches with CPU temp just like the other two fans are but at the minute they just sit around 600RPM shifting hardly any air and probably a total waste of space, any ideas how I can control them how I want?
 
Fan control options are a bit ambiguous, I have;

Normal - Allows the system fans to run at different speeds according to system temps.
Silent - Allows system fans to run at low speeds.
Manual - Allows you to control under the slope PWM function.
Disabled - Allows fans to run at full speed.

Obviously disabled is no good as it just runs them all at full speed with no control.

I've tried manual and altering the slope settings (of which I don't understand the values) but I've tried them all and nothing seems to change.
 
normal is what you want,pwm will ramp up and down according to temps aslong as its connected to a four pin fan header
 
That's fine, but my problem is that they never get fast enough to move a worthwhile amount of air, I can put my hand by the exhaust fan and barley feel anything which kinda makes them pointless, and seeing as the other one is the intake fan it's also debatable whether it's pulling in anything worthwhile.

This doesn't change regardless of whether I'm idling on the net or gaming.
 
Telecaster said:
That's fine, but my problem is that they never get fast enough to move a worthwhile amount of air, I can put my hand by the exhaust fan and barley feel anything which kinda makes them pointless, and seeing as the other one is the intake fan it's also debatable whether it's pulling in anything worthwhile.

This doesn't change regardless of whether I'm idling on the net or gaming.
Click to expand...

If that's the case then maybe the PWM curve needs to be steeper. Are you able to manually put them up to 100% through Speedfan and verify the speed response is as expected?
 
Tealc said:
If that's the case then maybe the PWM curve needs to be steeper. Are you able to manually put them up to 100% through Speedfan and verify the speed response is as expected?
Click to expand...

No, speed fan wont control them at all. I have another fan on a system header and it controls that fine (I have it set to a custom curve based on CPU temps) but these two case fans wont respond.

I think it's a clash of some sort, the other fans are BeQuiet fans that are actually 3 pin so aren't receiving any PWM signal from the header, does that sound feasible?

I didn't actually know the BeQuiet fans were controllable via software as I just assumed they were standard 3 pin fans and used to control them via a manual fan controller but got sick of constantly changing all of them between gaming and film/music/net browsing settings, the CPU cooler fan and one case fan work brilliantly (both BeQuiets) like this, it's just these two 4 pin Apaches I can't seem to make work.
 
Ok according to the manual..

http://download.gigabyte.eu/FileList/Manual/mb_manual_ga-z77(h77)-d3h(-mvp)_e.pdf

...

CPU_FAN has speed control on pin 2 and pin 4 so is good for 3 pin or 4 pin.

SYS_FAN1 has speed control on pin 2 and pin 4 is reserved (for what I've no idea) so sounds like it'll be good for 3 pinners.

SYS_FAN2/3 has speed control only on Pin 4 so is only good for PWM I suspect.

Also in the BIOS you should have options for 1st/2nd/3rd System fan speed. I wonder if these are to be controlled by the System temperature, rather than CPU.

Hey you could always buy a PWM splitter and just use the CPU header to control all fans you need.
 
Yes I was just going to reply that I should have RTFM, my bad, I didn't realise in my noobishness that headers had different pin configurations.

Question is now I don't understand the PWM slope settings, they are in range going up in increments like - '0.75 PWM/degrees C' up to 2.5 PWM/degrees C' - neither seems to make a difference so I wonder if like you say they work from system temp.

A PWM splitter sounds like a good idea.

Thanks and sorry for time wasting.

Edit: oh and another question, can 4 pin PWM fans be voltage controlled like the 3 pin fans? sorry if that's a stupid question.
 
Last edited:
Apaches can work off 3 pin voltage but the one I have was a bit crap as a 3 pinner.

2.5 PWM/C should raise very quickly. I'm not sure what the percentage starts with but that slope should be 100% duty cycle at 40 deg C above it.
 
Well system temp hovers around 25 at idle and never raises above 43 degrees when gaming or under load so probably explains why they don't speed up much.

With it set to 2.5 PWM/C they idle at 700RPM and max out at 1000RPM under load, which still feels a bit pathetic. Fan header splitter sounds like the best option.

Cheers for your help mate.
 
You must log in or register to reply here.
Back
Top Bottom