I'll chime in here.
I've had a 5820K since 2015, and many of you will be aware Haswell-E's were/are notorious CPU's for getting hot AF.
My NH-D15 handles it quite comfortably up to about 4.4 or 4.5GHz OC.
The 8700K is a much cooler CPU, if you're hitting over 70 degrees on an air cooler...