PWM fans are worth it

Control: management of fans, temp/rpm monitoring via soft/hardware

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

Post Reply
Derek Semeraro
Posts: 124
Joined: Sat Sep 23, 2017 6:49 am

PWM fans are worth it

Post by Derek Semeraro » Mon May 28, 2018 12:45 pm

In many cases, PWM versions of fans cost only a few dollars more. For some, this alone can make builds loud when they should be silent.

Non-PWM fans, at worst, will run at max speed if the motherboard doesn't have voltage control settings. But even if you are able to control non-PWM fans in your BIOS settings, it can be worth saving the time and hassle.

Olle P
Posts: 646
Joined: Tue Nov 04, 2008 6:03 am
Location: Sweden

Re: PWM fans are worth it

Post by Olle P » Wed May 30, 2018 3:57 am

I'd rather suggest:
Go with what your fan controller can handle!

If you use the motherboard to handle the fan speed, as is increasingly common, it's the fan headers and UEFI on the mobo that define what type(s) of fan to use.
If the controller only support voltage control for a case fan then use a fan that isn't built for PWM, because those typically can't handle low voltages as well.
If PWM support is available then that's better to use, but if voltage control is an option and you already have a perfectly good fan then use what you have.
Changing the setting from PWM to voltage control in the UEFI is by no means a hassle compared to all other adapting of the fan control required to make it run the way you want!

Derek Semeraro
Posts: 124
Joined: Sat Sep 23, 2017 6:49 am

Re: PWM fans are worth it

Post by Derek Semeraro » Fri Jun 15, 2018 3:01 pm

The amount of hassle is dependent on the particular motherboard's BIOS. You are right that before going for PWM or non-PWM, it's smart to check the specs and features of the motherboard first. I assume modern motherboards support PWM and will continue to for a while.

PWM is a forward investment overall. A 4-pin fan can be used in a 3-pin connection, but a 3-pin fan can never be a 4-pin fan.

Abula
Posts: 3607
Joined: Tue Nov 02, 2004 12:22 pm
Location: Guatemala

Re: PWM fans are worth it

Post by Abula » Fri Jun 15, 2018 6:27 pm

Derek Semeraro wrote:A 4-pin fan can be used in a 3-pin connection, but a 3-pin fan can never be a 4-pin fan.
Technically yes, in theory no, most of the manufactures of PWM fans recommend for them to be used only at 12V, there are some exceptions like noctua including a resistor with some of their PWM fans, but PWM fans are suppose to be design to be run at 12V always, weather some can be undervolted successfully is another matter, or the longevity, etc. Personally i don't undervolt my PWM fans, i have only done it to test but they behave erratically if you drop them low, in some cases the fan are spinning but no rpm reporting or the fan is spinning and suddenly it stops.
GameMi - Intel i9 9900K + Gigabyte Z390 AM + Asus RTX2080Ti Strix | MiniMi - Intel i7 8700K + ASRock Z370ITX + MSI RTX2080Ti
StreaMi - Intel i9 7940X + AsRock X299 Taichi + Asus GTX1080Ti Strix | WorkMi - AMD 1950X + AsRock X399 Taichi + MSI GTX1080
ServeMi - Intel Xeon E3-1230 + Supermicro X9SCM-F + 144TB | StoreMi - Intel Xeon E3 1240v5 + Supermicro X11SSM-F + 42TB | CamMi - Intel i7 4770K + MSI H81i + Blue Iris

Post Reply