Question Problem with h115i pro water coler

Apr 20, 2019
Hey, I'm new to the this build your own pc thing. I'm looking at the manuals for the msi mpg z390 gaming pro carbon ac motherboard and the corsair h115i pro water cooler and I noticed a problem. I plan on buying both of these products, and pcpartpicker told me that there were no compatibility issues with the two products. The h115i pro manual says "Connect pump tach cable to the CPU_FAN header on your motherboard (figure 1)" In the picture, it says "3 pin". However, in the motherboard manual, it says that there's " 1x 4-pin CPU fan connector". Are these two products incompatible? If not, where do I put the 3 pin tach cable? I appreciate any help.
Images of both manuals
Yes, it will work just fine. In fact, the cable you're talking about has only one function: it reports to the CPU_FAN header the speed of the pump unit of the H115i Pro system. Actually, in that system all of the monitoring and control is done by the iCue software utility from Corsair. But almost all mobos pay special attention to the fan speed signal on the CPU_FAN header and use it to detect FAILURE of the CPU cooler "fan". If it gets NO speed signal it often will take drastic action to prevent CPU overheating because of fan failure. So when using the H115i Pro system, it is important that the CPU_FAN header gets a valid speed signal. Moreover, it makes sense to have that be the pump speed, so IF the PUMP fails (not the rad fans), the CPU_FAN's normal failure monitoring system will catch that and warn you right away.

For more info on how the H115i Pro system works, see my post today in another thread here.