@puzzlezaddict Ah okay, I honestly know nothing about computers so apologies! Here should be a screenshot of all of my specs.
@ToxicViolets That's not the info I was asking for; I wanted the initial pop-up when you click About This Mac. But the model number in your screenshot gives me a good enough idea.
I still think it would be useful to try the default ultra graphics profile both with and without post-processing; make sure laptop mode is disabled as well. And try both fullscreen and windowed modes. You'll need to quit and restart the game for the changes to take effect, other than fulllscreen/windowed.
