How smooth is video playback of newer codecs or even higher resolution of any codecs at 4k? I thought about bringing back my w520 from the dead but the cost did

How smooth is video playback of newer codecs or even higher resolution of any codecs at 4k? I thought about bringing back my w520 from the dead but the cost didn't seem worth it. Coding videos below 1080p are harder to read and unless it's a school lecture, 720p is a minimum. And is it you main, do you have a separate system for media consumption?