My computer is a 2011 stock standard iMac with a 2.5Ghz processor. I trialled the latest version of X-Plane 11 on it and I couldn't use the menus. If I went down to choose an option they all disappeared.
Thinking I might need a new computer I checked at a computer shop only to be told the recommended hardware requirements were only available in a few very expensive stock computers.
X-Plane 10 has worked fine on my current computer, although it struggles a bit with the photo scenery of the UK that I purchased.
I expected that any of the latest iMacs should be quite capable of running the programme satisfactorily.