Hi. Many thanks for your reply. I've attached the log file, which might mean something to someone who knows about computers!
I've experimented with plug-ins- my system doesn't like running the Sundowner with Skymax Pro at all- removing this gives me 37 fps on low graphic settings with virtually no cloud selected in the weather menu. Looking out the cockpit side window towards airport scenery or significant terrain (mountains, etc) will cause the frame rate to drop to about 20fps and stuttering occurs- same at about 2,000 ft.
I frequently run aircraft from other developers with similar system demands and get by by just reducing the graphics settings- I can even run Colimata's Concorde, with it's complex systems without too much trouble.
System Specs are:
iMac (Retina 5K, 27-inch, Late 2015)
3.2 GHz Intel Core i5
24 GB 1867 MHz DDR3
AMD Radeon R9 M390 2 GB
Here are the log files. Any help would be much appreciated!
GizmoLog.txt Log.txt