The corsair H100i cooler fans run at 2300+ RPM under linux. Unfortunately, Corsair Link, only works in Windows and lm-sensors / fancontrol do not recognize anything but the pump RPM meaning you can't control the speed of the fans.
How do you control the speed of the fans under linux?
Corsair suggests that you connect the two fans to the control module via y-connecter. However, doing so under linux makes it impossible to control the fans and they will always run at 100% RPM.
If you connect the 2 fans to the motherboard (as chassis fans) you can control the fan speed as you normally would via lm-sensors and fancontrol (see: How to control fan speed?) , significantly reducing the sound level.
Connections would be as follows:
Fans x 2 -> Chassis Fan(s) on MOBO
Corsair Pump control -> CPU Fan on MOBO
USB > USB Header on MOBO
If you're not overclocking, the cooler unit is very unlikely to require management at all. For example, I have an i7-3930k running at stock frequency and the temps are staying between 32-40 at all times. Case is practically silent.
There's a port of Corsair Link that works on Linux:
http://www.voidbound.com/using-corsair-link-linux/
I tried it and it works.
I've come across this question when searching for a solution for my Corsair H100i PRO RGB cooler.
It is possible to connect it as instructed in the manual, and to control the speed by using OpenCorsairLink. https://github.com/audiohacked/OpenCorsairLink
