MacBook does not allow you to select a 4K resolution when connected to a 4K monitor.Here are two kinds of problems you might encounter: To run a 4K monitor at 60 Hz requires the right combination of hardware, cables, and adapters. A higher refresh rate results in a smoother picture, which is why an iPad Pro screen that refreshes at 120 Hz is smoother to use. The refresh rate on the MacBook retina displays is 60 Hz, which means the screen updates with new images 60 times each second.
This, though, is the root of the problem. Now, the external display can be on par with the retina screens' crispness and clarity.
4K monitors have only recently become mainstream. The problem starts when we start hooking up an external monitor to match the clarity and DPI of the MacBook’s retina screen i.e., a 4K or 5K monitor. It’s no fault of our MacBook’s though - this is the tradeoff we make for portability. With many of us knowledge workers working from home in the COVID-19 era, our trusty Apple MacBook’s retina displays often need a bigger friend to take over the display duties.
