/ Sign-up
Your question

(ASUS M4A78LT-M) Fans running full speed despite Q-Fan being enabled

  • Motherboards
  • Asus
  • Fan
Last response: in Motherboards
December 19, 2010 1:53:12 PM


recently got a new computer with this motherboard in it and for some reason Q-Fan doesn't seem to be doing its job. It's enabled in the BIOS, but the chassis fan is running at 3000+ RPM and the CPU fan at about 2800+ RPM. Temperatures are at about 30 degrees celcius, and Q-Fan is set to kick in to full speed at 60 degrees celcius.

What can I do? Please, any help would be greatly appreciated.


More about : asus m4a78lt fans running full speed fan enabled

a b V Motherboard
December 19, 2010 6:40:26 PM

Q-FAN only works with fans that utilize 4-Pin PWM controls, and are of course connected directly to the motherboard.

If you don't have these, it won't do anything,
December 19, 2010 9:03:31 PM

Not having opened it up yet, and unfortunately not being around the computer right now, I'm unable to tell whether it does have an appropriate fan - I just presumed, since the motherboard is able to read and report the fan's speed values in RPMs, that they should be able to be controlled too.
Related resources
a b V Motherboard
December 19, 2010 9:59:18 PM

Some motherboards do control the fans by RPM monitoring, but Q-Fan is not one of them. It controls by power output, and uses PWM to ensure accurate controls.
When it comes to fan connectors:
2pin = Power only
3pin = Power and RPM monitor
4pin = Power, RPM monitor, and PWM control
a b V Motherboard
a b Ĉ ASUS
December 20, 2010 5:13:59 PM

You can control 3-pin fans but you need to associate the fan with a temperature and the motherboard will change the voltage on that fan to try and reach that target temperature. I believe you can also specify a specific voltage for the fans too. usually between 8-12 volts.