Your right with the 64bit so you will be looking for one of the Pro versions of Poser as the non pro versions of Poser are 32 bit.  The big plus with 64bit it can use all of your RAM, sometimes dependant on the OS used, making complex scenes possible.  Animation wise, it depends what you are looking to do as many will advise that Poser is not the best package for animation.

 The general understanding is that the more cores you have the faster the render so you are probably looking a CPUs with lots of cores and hyper-threading which give you double the cores by adding virtual cores.  The other way is to use multiple CPUs either in a single system or by networking multiple systems.

The other important decision is, are you building it yourself or having it built either off the shelf or customised.  This is important, as building yourself can often give you bigger bang for you buck.  You also say that the system is primarily for Poser but what else are you using it for?  Video work, audio work, gaming?  All these functions can change configuration in some way.

All very general advice to get you started I know you will get a lot more, be sure of what you want to do with the system and where you might want to go over the life of the system is a good starting point. 

 

 

 

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.