I also use the Threadipper 1950X along with a GTX 1080i which I have been using for about four years. I render at 3508 X 2480 and I have been using Superfly for the last three or so years. Poser 11 did not like the 1080i very much but it is fine with Poser 12 and that is what I use most using the Ultra Adaptive load preset. The only time I have a crash is when I send a complex scene to the GPU when the render will either fail or Poser will lock up. In these cases I switch to using the CPU which utilises all 32 threads and I have had no problems. Although I had the system professionally built with a free option to have it overclocked I decided to keep it standard.

 

 

I use Poser 13 on Windows 11 - For Scene set up I use a Geekcom A5 -  Ryzen 9 5900HX, with 64 gig ram and 3 TB  storage, mini PC with final rendering done on normal sized desktop using an AMD Ryzen Threadipper 1950X CPU, Corsair Hydro H100i CPU cooler, 3XS EVGA GTX 1080i SC with 11g Ram, 4 X 16gig Corsair DDR4 Ram and a Corsair RM 100 PSU .   The desktop is in a remote location with rendering done via Queue Manager which gives me a clearer desktop and quieter computer room.