PWM fan controller for an eight year old PC?

Hello chaps! :)

I have a EVGA 790i Ultra SLI motherboard that just wont quit and the system built around it is fine for my needs.

However, it could be quieter so I purchased four of those Corsair ML120 fans but soon realised that they are PWM only once I heard them creating a high pitched whine when I dialed down the voltage on my fan controller.

So I don't really want to get rid of the fans but they are really noisy in my system because I have no PWM controller on this board.

I cannot find a PWM controller apart from the Zalman Fan Mate but that is reaaally hard to source. I guess no one want to buuy this tech because it is on all mobo's nowadays. I don't care about the temperature control either I just want to slow them down so they don't whine.

So does anyone have any suggestions on this rather niche requirement?

Tried Overclockers? ▷ Fan Controllers | OVERCLOCKERS UK.