I’m running X-Plane on a 2017 iMac (Specifications see signature). When I run the Toliss A340 my FPS drop below 20 FPS sitting at the terminal of LSZH or EDDF on a freshly installed 11.55 X-Plane version on a Samsung X3 USB connected drive (one 250 gb HFS+ and one 250 gb FAT partition)
The only non-standard add-ons installed are SAM-3, Avitab and Aerosoft Zurich (all current versions) 

Just out of curiosity I decided to install X-Plane on my Bootcamp Windows 10 installation to see what kind of performance I would get there.

I performed the same installation, i.e. fresh X-Plane, Toliss A340, SAM 3, Avitab and Aerosoft Zurich.
To my surprise I was running at 30+ FPS on the same hardware. 

Has anybody had similar experiences or can anybody explain the difference? Is it Vulcan vs Metal or Windows vs Mac OS?

Edited November 24, 20213 yr by robder

I have the same identical Mac as you (late 2017), however have not tried Windows on Bootcamp.  I'm interested to see if any others have experienced similar performance increases with a Windows Bootcamp system.

Do you see similar increases in performance with other planes/scenery when running them on Windows?

Thanks, Bruce.

'

Yes I did, I performed some standard laminar tests.

see result and other feedback here:

 

Thanks.