[Corsair Link] RPM-Display?

I already posted this here but it seems that the activity in the german forum isn't that big.

Hope it's okay to ask it here again:

 

I connected the pump-cabel of my H115i to "CPU_FAN1" but Corsair Link and HWMonitor are showing there a RPM-Value that makes no sense to me, because i already see Pump Speed + Fan Speed under "H115i".

 

Can someone explain, please?

 

http://fs5.directupload.net/images/171116/temp/9frxtqlc.jpg http://fs1.directupload.net/images/171116/temp/z6dsfl42.jpg

Most AIO pumps work differently from a standard fan (which is what your motherboard is expecting when you plug something into a fan header). The correct RPM is what the H115i is reporting.

Here's a copy-paste from Asetek which manufacturers most pumps used in AIO coolers:

"The tach signal is rather simplistic. It is designed to count the number of times a motor pole passes a certain point. Most fans use 4-pole motors. When the liquid cooler pump is plugged in, it reports the number of times the pump motors poles pass the same point, but the pump only uses a 2-pole motor. Because the BIOS is expecting a fan, it divides its tach signal count by 4 and only reports half the speed of the pump."