One thing that they didn't mention on the article, but it was talked about at the Metal 2 WWDC sessions, is that they ported the Window Manager from OpenGL to M

One thing that they didn't mention on the article, but it was talked about at the Metal 2 WWDC sessions, is that they ported the Window Manager from OpenGL to Metal 2. Note that this is mentioned in the article: Apple says the entire WindowServer is now using Metal, which should improve the fluidity and consistency of transitions and animations within macOS; this can be a problem on Macs when you’re pushing multiple monitors or using higher Retina scaling modes on, especially if you’re using integrated graphics.