Apple deprecated OpenGL on Mac with MacOS 10.4, Mojave. My understanding is that MacOS 10.5, Catalina, to be released this fall, will remove support for OpenGL altogether, although I don’t know if that’s official. I do know that Apple game developers have been forced to use Metal instead of OpenGL.
The low res monitor helps, but your best bet is to reduce the frame rate on the Mac, as mentioned elsewhere.