Hello, everyone! I really hope you can help me out, or at least give me some guidance. So, the computer that I have is 2015’s Macbook Pro ‘15 with pretty much spec out specs, except there is no dedicated amd’s graphics card. Its a refurbished model, bought from Japan’s Apple store. The machine is currently running MacOS Sierra latest build (10.12.6). In general, laptop is working just fine, but what bothers me is UI. Its pretty sluggish. I mean when you open, for an example, launchpad (especially launch it when you are being, for an example, within Safari environment) and try to open, for an example, sub-folders, like “other”, you get edgy, choppy animations, while trying to run any app within that folder... Somehow, it gets sort of fixed when plugging the laptop to an external monitor, but I guess its because it automatically changes to non-retina resolution, to external monitor's resoluton, which is full hd. I’ve downloaded an app that helps changing resolutions, so when I change to something, not retina-ish, like 2500x1600 or something like that - it pretty much fixes the whole thing, but because its not retina resolution, the text looks not so sharp and so on. Why this is happening? Is Intel Iris Pro integrated graphics not enough to run smoothly retina resolution? But I doubt it, because why the hell Apple would release laptop with not powerful enough igpu to run basic macbook's operations. My sister has same macbook, with slower cpu - she said UI runs just fine. Appreciated.