I have had the same issue and I have a 1080ti with 11Gb on board with just one figure and a couple of props.  In my case it has always been traced back to a problem with using older content so I would suspect Poser 4 content might be and issue.  As I found out in an earlier thread today, once you have had a CUDA failure you will need to restart Poser before you can do any more GPU renders.

 

 

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.