I’ve had a CLC 360 radiator for about a year, it works great and all but I just started noticing a strange behavior on my unit. I recently upgraded my PC and decided to mount the CLC radiator horizontally at the top of my pc, previously it was mounted vertically in the front. In this new position though I realized the fan noise was much more noticeable. So I decided to finally download the flow control software to adjust fan curves and such. 
 
According to the CLC product page the fans should be rated for 500-2400 RPM. However when I take manual control of the fans the lowest I can set the RPM is 960-1020 RPM which is around 40% of the max speed. Even if I adjust the fan curve to be a flat line which according to the software should bottom out at 25% or 600 RPM the software still reports that the fans are in that 960-1020 range. Is this expected behavior of the software or could my fans/unit be faulty in some way which is causing them to run at a higher RPM than expected?