I'd start with turning off "Multicore enhancement". I can see it dipping to 1200mhz occasionally, which should never happen during gameplay. Meaning it's thermal throttling at the VRM's.
WHich isn't weird considering you're boosting a 12 thread CPU to 4.3ghz all-core boost on a very, very meager VRM.
Even if they use decent components, that's either a 3+3 or a 4+2 setup. Nothing you really want to run an OC 8700K on.