Contolling Rad fans by GFX card PWM?

RichH · 31 Aug 2012 at 12:06

Anyone tried this?

I am doing a GPU only loop and was wondering if i could use the PWM fan headers on my graphics cards to control the rad fans.

Anyone either done this, know how to do it or just have any thought on it?

Sir SpankalotUK · 31 Aug 2012 at 12:29

I would be careful, the current draw of a fan on the gpu will likely be a lot less than a 120mm fan, especially at startup.

Going by 60mm vs 120mm fans, 0.8watts vs 3.5watts
(quickly reading from products on OCuk)

A fan controller will offer you more freedom and you wont have to worry about potentially damaging an expensive gpu.

twist3d0n3 · 31 Aug 2012 at 13:52

you could always just take the pwm signal and run them off the psu, that way you can control them from msi ab for example, but not put the card under much stress

you'll have to mod the connector tho

RichH · 31 Aug 2012 at 14:26

That is what i was thinking, just take the PWM cable from a GPU and get the power from a molex or mobo header.

twist3d0n3 · 31 Aug 2012 at 15:54

of course, you could just run it off the cpu header... all of my pwm's (9 in total) are running off that

RichH · 31 Aug 2012 at 15:55

Yeah but that would respond to CPU temp, not GPU temp.

twist3d0n3 · 31 Aug 2012 at 16:51

why is it so important? if you're running water, you don't really need to turn the fans up...

at the moment mine goes from 20% at idle to 40% IF cpu temps get near 90. gpu's never get anywhere near as hot

andybird123 · 31 Aug 2012 at 17:04

gelid do a mini pwm to normal pwm adaptor - then you'd just need to cut the 12v and splice in one from a molex adaptor

RichH · 31 Aug 2012 at 17:09

andybird123 said:
gelid do a mini pwm to normal pwm adaptor - then you'd just need to cut the 12v and splice in one from a molex adaptor

Ah, thanks for this, that is what i was looking for. Will i be able to control 3 fans with the signal from 1 mini PWM header?

RichH · 31 Aug 2012 at 17:10

twist3d0n3 said:
why is it so important? if you're running water, you don't really need to turn the fans up...

at the moment mine goes from 20% at idle to 40% IF cpu temps get near 90. gpu's never get anywhere near as hot

Good point. Perhaps I should wait and see what temps are like. I may be able to just keep fans at 30% so PWM wouldn't be needed anyway.

twist3d0n3 · 31 Aug 2012 at 17:44

yeah. at 1st i was all about fan speed control for my rads; now i'm all about absolute silence. tbh i might just set the fans to stay at 20% constantly - it's only in the summer with a heavy OC that it really makes a bit of a difference, and even then it doesn't really matter