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dorianbz · ‎04-25-2014

Hello everybody,

I'm new here 🙂

I have a brand new pc, everything working well but I have a doubt about something

I bought the PC already mounted, and the in the asus suite I noticed the rpm of the both fans are differents
the CPU_FAN is 1460 rmp and the other CPU_OPT is 762 rpm

I imagine it's because the seller plug each fan to different fan plug but these 2 fans are the part of the same watercooling process

Aren't they should run both at the same speed?

I read on forums that there is a Y cable to plug the both fans to the unique CPU_FAN

Based on your experience do you recommend me to do the change? Is it better for the fan to be controlled by one connector or two like it's setted now?

Thanks for you help and sorry for my english 😮

Chino · ‎04-25-2014

Welcome to the ROG forums, dorianbz.

Connect the pump to the CPU_OPT header and the fans to the CPU_FAN header. That way you can control the speed of your fans and your pump will always run at 100%.

dorianbz · ‎04-25-2014

Hi and Thanks Chino

Indeed the pump is connected to the OPT_FAN3 is it the same as the CPU_OPT?

the speed of the pump is 2300 rpm, it seems to run always at this speed

Chino · ‎04-25-2014

That is correct. The pump will always run at full speed so it doesn't really matter where you plug it into. I like to use the CPU_OPT header.

dorianbz · ‎04-25-2014

Ok so for the two connectors of fans you recommend me to use the Y adaptater cable to plug in only one connector, the CPU_FAN

the way they are connected seems weird but they offer me a good cooling my CPU is 25°c but the problem should be the noise.

if the both fans turn at the same speed, how many rpm you think it will use.

Veracis · ‎04-25-2014

The fans on your radiator (single or push pull) should be connected to the CPU_Fan header (with a y connector if using 2 fans) The pump has its own connector and you should put that on the CPU_Opt header. In AI Suite 3 my CPU_Opt is running at 2299 all the time.

dorianbz · ‎04-26-2014

Ok 🙂

the fans are not in push pull just 2 fans side by side.

dorianbz · ‎04-26-2014

the sensor

http://imgur.com/IsAs81D

as you can see I have the chassis Fan in orange, maybe it's too slow

dorianbz · ‎04-26-2014

I did several tests
I switch off Q-fan control to see what happen

I note that the OPT_FAN running full speed more than 2000 rpm but the CPU_FAN still at 1400 rpm absolutely no speed variation.
Did the OPT_FAN take control and the PWM of CPU_FAN is not controled anymore?

Only CPU_OPT seems to control the speed.

The fan plugged in CPU_FAN don't respond well or is it normal?
I don't know what to do 😞

Veracis · ‎04-26-2014

Whichever is connected to the pump should maintain a speed >2000 rpm. The PWM fan (4 pin) should be able to be controlled via AI suite or in bios. You do not change the q-fan control unless you have a 3 pin fan you want to control. If your Fan xpert cannot control your fan make sure it is plugged in correctly and make sure your fan xpert is working properly IE does it control your case fans or are those static as well?

Also the speed of the fans is dependent on your temperature curve you set. If the temps are low enough the fans wont spin. Put your setting to full speed and see if your fans run.

CM Seidon 240 Fan connection with Rampage IV