PWM fan splice

[stuman]

So I have done a fan swap on the graphics card for 2* 120mm fans.

They are rated to spin to 2200 rpm, however max I have seen is 1600ish.

Would this be a limitation of the GPUs 12v rail and current draw of the fans? I have checked settings in the Wattman settings and it looks fine.

So next idea is keep the GPUs pwm signal lines running to the GPU’s fan header but to use a 12v rail from the PSU. In my thinking, this can also free up some more wattage to dump back into an Overclock?

Any advice? Anybody done something like this? Is there a ready made cable available?

 

[Tealc]

I doubt if the fan current is your limiting issue. I'd expect it to take its power direct from the 12v supply.

Check your card is pushing 100% PWM to see what the fastest fan speed can be.

I suspect 1600rpm across 2*120mm fans will be more than you ever need though.

As for a cable to take 12v and ground from motherboard and provide tach and pwm from card sounds very much like custom cable territory to me.

 

[LuckyBenski]

Custom cable indeed. I would make sure you're only reading speed from one fan. If you wire both fan's tach wires to the sensor/socket, the card won't be able to interpret it well.

You could also just wire the fans direct to your motherboard/fan controller.

 

[stuman]

I use the the Wattman ati software to ramp the fans when it needs, so mobo’ headers Out of the question

Is there a pwm fan controller which takes power from a PSU line?

 

[stuman]

Deleted, double post

 

[LuckyBenski]

I use the the Wattman ati software to ramp the fans when it needs, so mobo’ headers Out of the question

Is there a pwm fan controller which takes power from a PSU line?

There are simple splitters that take power from PSU and distribute the PWM signal from motherboard to all fans.

Any more advanced fan controller I assume would also take power direct from the PSU.

 

[EsaT]

Is there a pwm fan controller which takes power from a PSU line?

Any separate fan controllers draw power from PSU.

 

[doyll]

I would probably make adapter from GPU fan header and PSU to fan using GPU header plug for PWM control and rpm with Sata or molex plug for 12v and Ground from PSU all gong to PWM fan socket.

Below is an example with more connections than you need. Mini PWM connector is to GPU. Molex could be Sata, your choice. Mini PWM you probably don't need, or the rpm lead in a fan plug. Just use the Mini PWM connector to GPU for PWM signal control and rpm reading, Sata or Molex from PSU for 12v power and ground .. all to PWM fan socket/s for your fan/s

 

[stuman]

Apart from the mini header that was pretty much what I had planned.

I however took the lazy way out and bought a little box to do the job.

I’ll post back.