> Should I try using madVR then and see if it fixes my problem?
it's worth trying...
install it via SVP's "Additional programs and features" and then switch the video renderer in MPC-HC's Options -> Playback -> Output
It looks like with madVR it works fluently!
Tho it uses about 20% more CPU and 15% more GPU, but that's worth it I'd say.
Thank you for your help!