PWM Fan Headers

Swi1ch · 13 Apr 2020 at 04:14

The rough system I have in mind to build has more PWM Fans than there are on the board (3 front, 1 rear, 2 on the AIO radiator, and 4 fan headers). The board has two CPU headers, a rear header, and a front header.

Can I use this https://www.overclockers.co.uk/ek-water-blocks-ek-cable-splitter-4-fan-pwm-extended-wc-9cq-ek.html to connect the front three fans to the front header, just plug and play? Anything I would have to consider?

Jamin280672 · 13 Apr 2020 at 04:52

Swi1ch said:
The rough system I have in mind to build has more PWM Fans than there are on the board (3 front, 1 rear, 2 on the AIO radiator, and 4 fan headers). The board has two CPU headers, a rear header, and a front header

Can I use this https://www.overclockers.co.uk/ek-water-blocks-ek-cable-splitter-4-fan-pwm-extended-wc-9cq-ek.html to connect the front three fans to the front header, just plug and play? Anything I would have to consider?

Yes that will work perfectly fine, the fans will get there power from the molex connector and just the pwm signal from the motherboard.

one of those fan connectors will have 4 pins, the other 3 connectors will have 3 pins, make sure you use the one with 4 pins and then any other the other 3 connectors on that cable for your other fans, although they are still for 4 pin pwm fans, they are just missing the rpm pin the motherboard only needs rpm signal from 1 fan.

I have one of these, although I see its now discontinued, just google "Phobya PWM 8 x 4pin Fan Splitter", it does the same thing, I have one of those laying around somewhere too, I have 5 fans connected to mine all getting there signal from the CPU fan header: https://www.overclockers.co.uk/xspc-8-way-pwm-splitter-hub-sata-powered-black-fg-004-xs.html

C64 · 13 Apr 2020 at 10:17

Are there no issues overloading a board fan header these days ? you'd think all boards would come with at leasst 5 pwn headers these days

Jamin280672 · 13 Apr 2020 at 10:29

C64 said:
Are there no issues overloading a board fan header these days ? you'd think all boards would come with at leasst 5 pwn headers these days

All of those adaptors listed above supply the power to the fans directly from the PSU, the motherboard only supplies the PWM signal for speed control.

doyll · 13 Apr 2020 at 17:41

C64 said:
Are there no issues overloading a board fan header these days ? you'd think all boards would come with at leasst 5 pwn headers these days

What Jamin280672 said. Because all PWM fans plugged into splitter are being controlled by same PWM signal it is best to have all the same fans (or at least fans with similar ldle and top speeds) so they will all be running at similar speed.

Most motherboard fan headers are rated about 1amp/12watts. Water pump headers are rated higher. But keep in mind a fan with 4w rating (usually running load rating) draws 3-5 times for a very short time while starting up (much longer if something is stopping impeller from turning). Basically this mean a fan header is only good for 2, maybe 3 fans. Even 3 fans might draw more than 1a at startup. If you know or have heard of anyone who has burned out a fan header it almsot always happens at startup .. when fan are pulling 3-5 times more power.