Question how to lower minimum fanspeed asus gtx 760 dcu ii after fan mod

[homie_______________]

I have swapped the fans on my asus gtx 760 dcu ii with noctua nf-b9 redux. To retain proper pwm control directly from gpu, they are wired to original plug. The original fans ran at a max of around 3000rpm and 700mA combined, the noctuas run at 1600rpm and 200mA combined. Now msi afterburner maxes out the fans at 55% fan speed, anything above this does not change the speed anymore. The minimum i can drag the slider to is 29%. At 29% the fans run at over 1000rpm and is too loud for idle. How can bring the minimum fanspeed down? I am familiar with kepler bios editor but there is no entry for fan control. Last ditch effort ofc is a physical switch to turn em off... fan controllers or a faster fan lol. thanks

 

[Lutfij]

Welcome to the forums, newcomer!

If you followed a guide off of YT, I don't think that video explained that all fans have a minimum voltage in order for the fans to turn even one rotation before they don't need that same voltage to continue turning. As such you've found out that the fan you modded into, doesn't like any voltage below 29%.

I would highly advise on not introducing anymore switches in the GPU fan's circuitry. Perhaps add resistor(s) but then your temps and performance might suffer in the long run, making this mod pointless to begin with.

 

[homie_______________]

after measuring with voltmeter the fans run at 12v at all times and the speed should be modulated by pwm signal, which the fan slider in afterburner does by the percentage of original design fan speed im guessing... either that or by the pulse duty cycle... idk but not by voltage. according to noctua specsheet they should start at 5v and are rated for minimum pwm speed of 350rpm. 29% of 12v is 3.48v so the fans wouldnt be spinning at all if by voltage control like in a psu. 29% of 3000 happens to be 870 which seems to be close enough to my problem 1000rpm fan speed reading by tach... 55% of 3000 also happens to be 1650, about the max rpms of the noctuas. the tach seems to reads about 200rpm over actual speed but thats whatever tbh but worth noting. im guessing the fans are controlled by some ic somewhere with its own firmware/hardlocks and trying to lower minimum fanspeed may be a fruitless effort. in the meantime i will also appreciate suggestions for quiet>2000rpm 92mm fan... lol