Have you run the CPU and GPU through torture tests like Intel Burn Test, Prime95 and Furmark? Of course monitor the temps as they are being run. Although if Dolphin crashes at startup, it likely isnt a stability thing.
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