Non-PWM Fan on a PWM Fan Header

Is it possible to run a 12v fan (3 pin non-PWM) on a MOBO PWM fan header (4 pin)? If so, will it just run at full speed only or would I be able to control the speed somewhat?

No...I've got Two of my 3pins Pc case 12v fans plugged in the motherboard 4pins PWM and they still available in the monitoring speed software. I can easily set parameters speed on them.

NoN said:

No...I've got Two of my 3pins Pc case 12v fans plugged in the motherboard 4pins PWM and they still available in the monitoring speed software. I can easily set parameters speed on them.

"Curiouser and curiouser," said Jeannie (apologies to Charles Lutwidge Dodgson), especially since my MOBO uses the same software (AI Suite II). This is good to know. Thanks!

crawfish said:

You Asus users might find this thread interesting:

ASUS Z87-Deluxe fake 4-pin headers & other fan control info

Humm...my mobo have 4 headers with 4pins. I can plug two of 4 pins PWM fans (CPU_Fan & Cha_Fan) and still have the speed control in Bios (set to manual setting) & set my testing parameters in Ai Suite II software.

The two others 3 pins PC Case are also set "manual" in Bios according my demand to reflect them in AI Suite II software.

Since I can control the low/mid/high RPM percentage according to the CPU Temp and test the fans speed with Fan Xpert+, i don't see any issues in that right now.

Thanks for the link, might dig that a bit!

On screenshot it shows % w/Temp regulation for a 3 pins Fan plug on 4 pins header.

I have a P9X79 WS (as in Work Station) MOBO. I took a look at my manual (yeah, I actually keep it handy and use it) and all four of the chassis fan headers show the following connections:

CHA FAN PWM
CHA FAN IN
CHA FAN PWR
GND

Nothing is mentioned about any voltage, let alone +5v. There are no little switches by the headers either. Methinks my MOBO actually does support true PWM (after what I paid for it, it bloody well better!).

Lady Fitzgerald said:

I have a P9X79 WS (as in Work Station) MOBO. I took a look at my manual (yeah, I actually keep it handy and use it) and all four of the chassis fan headers show the following connections:

CHA FAN PWM
CHA FAN IN
CHA FAN PWR
GND

Nothing is mentioned about any voltage, let alone +5v. There are no little switches by the headers either. Methinks my MOBO actually does support true PWM (after what I paid for it, it bloody well better!).

Screenshot shows mine either...:)

crawfish said:

FWIW, my two 3-pin case fans are attached to 4-pin headers on my Asus Gryphon Z87 which has the "fake" PWM chassis fan headers, and the BIOS controls the speed, while AI Suite III provides finer control inside Windows. I've set them to idle around 480 RPM, while the CPU fan (true PWM) idles at 200 RPM. They all ramp up with CPU temp. Works great. Per that thread I linked to, PWM fans attached to the fake headers are still controllable to some extent, and it's subtle to determine from their behavior if you're getting "real" PWM.

To the OP, YMMV with other motherboards and software.

Might some 3pins fans got RPM Signal and very basic ones don't. But i do think when using 4pins PWM on those described headers its still be kind of PWM as schema shows it. Yes, Q_Fan for CHA_FAN in bios have slight different setting than the CPU_Fan.