Hello, I can get a 2015 Macbook Air for free (girlfriend) but i will want to use it as a desktop too with an external keyboard, mouse and of course monitor. I was wondering if the Air can drive a 4K screen without lag? I use Sketch and Camera RAW/Photoshop quite a bit (i'm a photographer) which are quite heavy apps. I wouldn't want any lag when using a scaled resolution during animations, nor having the fans to spin 24 hours a day. Does anybody have some insight in this? If 4K seems too much, i'm considering a 2K screen too. But i'm not sure how crisp those are (and future proof).