I hope this isn't a completely unreasonable question or a waste of anyone's time.I have an early 2008 Mac Pro with dual, quad-core Xeon processors running at 2.8 GHz. So far, I've been able to upgrade it to keep up with X-Plane's requirements including a solid state drive, 16 GB RAM and the Nvidia GTX 906 with 4 GB VRAM. It runs XP 10.5 acceptably (frame rate 25 - usable though not ideal), but the 11.02 demo frame rate is only 9 to 14. I realize this machine could charitably be described as a dinosaur, and that I will have to replace it sooner rather than later. However, based on the minimum and recommended system requirements, it seemed reasonable to hope that XP 11 would not perform that much worse than version 10.5.
Different combinations of graphics rendering options in XP 11 result in only small changes in frame rate. The X-Plane.org forums suggest that this may be due to Threaded Optimization being on in the video card. Windows users can easily turn this off with the Nvidia control panel, which apparently does not exist in Mac OS X (10.11.6.)
If anyone knows how change Threaded Optimization on a Mac (perhaps using Terminal commands or scripts?), I'd appreciate your help. Alternatively, might there be a way to tweak XP 11 to eliminate the conflict with the video card? I'd greatly appreciate any help I can get, even if the verdict is that there is no way to fix this problem. Thank you very much.