Here’s the problem with external displays connected to Mac notebooks. Controls. OS X Yosemite does not include the option to set specific screen resolutions. To get that control back, and to be able to set an external display to the resolution you want, you need Display Maestro. This inexpensive Mac utility has one function in life. Manage screen resolutions on external displays connected to your Mac.
Here’s what it looks like in action.
Using Display Maestro is simple enough. It resides on your Mac’s Menubar so it’s accessible from within any Mac app. Screen features are many and varied so Display Maestro keeps it simple. It displays information specific to the display that’s connected to your Mac.
That includes various display values and capabilities, manufacturer and date, plus other properties in the display (HiDPI capability, AirPlay, OpenGL acceleration, size, modes, and more). Then it controls all supported resolutions from the Menubar, adds the option to toggle a list of other resolutions, restore standard ColorSync settings, view gamma and RGB points for the display.
Settings are often dependent up variables from the display and your Mac’s graphics card, but Display Maestro maximizes what you’ve got. The simple option to display an external screen’s various resolutions is worth the nominal price tag on its own.