Hello, I attached a picture in this post with the details of my system. I just bought an LG 27UK850-W and I have serious performance problems. Even with the naked eye, it's pretty obvious when I perform quick moves. When I try to watch a YouTube video at 4K, it's stutters really really bad, it's unwatchable. I've connected the monitor via USB-C (the one that came with the monitor) and under Settings it's displayed 60Hz. I tried everything, I've searched online for solutions for two days now. Do you have any idea why I have this problem? It's just a hardware limitation from my Macbook (even if I read online that users have no problems running 4k even with older Macbooks) and I can't do nothing about it? Maybe a factory reset will work? That's pretty much my last resort. Also, I'm wondering if maybe it's the cable to blame. The thing is that when I watch a 4k Youtube Video, under Activity Monitor, the CPU is really stressed out.