This depends on the game but if memory serves, the big CPU drains are using LLE, EFB to RAM and enabling XFB. So any games that require one (or more) of these are likely to give you slowdowns.
i5-8600K @ 4.5 GHz
GeForce GTX 1080 SC2
ASRock Z370 Taichi LGA 1151
CORSAIR Vengeance LPX 16GB 2400 DDR4
SAMSUNG 970 EVO M.2 500GB PCIe SSD
Indigo Xtreme TIM
Phanteks Pro ES614P Black Steel Case
EVGA SuperNOVA 750W PSU
Windows 10 64-bit
GeForce GTX 1080 SC2
ASRock Z370 Taichi LGA 1151
CORSAIR Vengeance LPX 16GB 2400 DDR4
SAMSUNG 970 EVO M.2 500GB PCIe SSD
Indigo Xtreme TIM
Phanteks Pro ES614P Black Steel Case
EVGA SuperNOVA 750W PSU
Windows 10 64-bit