One of the problems with adding the runtime to the desktop is, I believe, that Windows will load it each time the PC is strated so a large Runtime could slow Windows when loading.  I say 'believe' as I think this was the case but not sure with Windows 8.

Another factor could be the hardware on your machine.  If the C drive is a Solid State Drive, and by default the desktop lives on the C drive, You might want to place the Runtime on a conventional drive to reduce the read /writes to the SSD and extend it's life.  This is what I have and the Poser Temp files are moved to my D drive along with all other temp folders and my Runtimes, 40 individual Runtimes, are on my E drive.  Both my D and E drives are conventional 2Tb drives leaving my C drive for Windows and programs only.

 

 

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.