Question CPU Cooler Fans Surging

[Meshkeen]

Hey everyone, I just built myself a pc a couple months ago:
Intel Core i7-8700k
32GB of DDR4 3200mhz RAM
Z370 AORUS Gaming 5 mobo
EVGA NVIDIA GeForce GTX 1080Ti
650W psu
Masterliquid ML240L RGB Liquid AIO cooler

My cpu cooler fans keep surging from 800rpm to 1900rpm for a couple seconds and then back down again without any noticable temperature spikes. The waterblock cooler doesn't seem to be surging, just the 2 additional fans that came with the cooler that are mounted on the radiator.
I was a little confused as to which fan header I should plug the 3 of those into so as of right now it is:
CPU waterblock -----> SYS_FAN5_PUMP
2 Fans on Radiator ----> CPU_FAN

Any help is appreciated along with help telling me if I plugged the cooler in the wrong place.

Thanks

 

[tennis2]

What does your fan curve look like in the BIOS? You may have too aggressive of a curve set.