Well after several days of no lock-ups or crashes to the desktop I think I finally found a sweet spot to get this game working.
I have one of the newer 27" iMacs, with 16gb of Ram and The Nvidia 680mx card with 1TB Fusion Drive.
After tweaking around with the settings I found a combo that sacrificed the least and was the most stable. I dropped the resolution down 1 notch from native and run the program in a window rather than full screen. Not really an issue with the large 27" screen. I also changed all the graphic settings to medium with the exception of Texture Detail which is on High. Reflections are set for Mirrors only. I did not disable Advanced Rendering. I wanted to find a combo that worked with Advanced Rendering on. Turning it off makes the game very unappealing.
Using this combination I've been able to play for several days without any crashes or freezes at all, for hours at a time. I have these expansions/packs installed: Ambitions, Generations, Late Night, Showtime, High End Loft, Fast Lane, Supernatural, Seasons.
