Round shapes have corners when zoomed in

Hey all,

I've noticed that when I'm drawing round paths, if I zoom in as far as I can go, the smooth lines become cornered and that's rather annoying to see. I set the stroke to round corners and and caps and it's something I've never noticed before, which I think is weird. I've tried to use the CPU view, and that solves the problem, but it slows down drastically the overall performance, like zooming in and out and moving around the working area, it does get reaalllllly slow, and I've never had to work like this. Is it possible that it may have always been like this and I've only just noticed or maybe there's some weird setting that has changed or something is happening to my MacBook? Tips on how to solve this? These are my specs and below is a picture of how the paths look when I zoom in. Thanks in advance.