I was using my MacBook pro for years with two external full HD displays without a problem. Recently I switched to two 4K displays and since then fans in my MacBook spin all the time when when hooked up to external screens. I see that WindowServer spins at 20-30% CPU most of the time even if I do some basic activities.
Is this something expected or is it fixable and how?
I'm on High Sierra 10.13.6 with 16 GB ram, i7 and GeForce 750M with 2GB ram.
When I tried to watch some 4K youtube video I experienced stutter and overall poor playback quality. The same video in Full HD runs smooth.
I tried the same on Mid 2015 MacBook Pro equipped only with Intel Iris and it has no problem supporting 2 external 4k screens. Does one year in those models makes such a big difference? Or there is something wrong with mine?