My SSD is used by Windows for the OS and programs and by HW for the cache files. I keep the samples and definitions on a hard disk drive (which Windows sees as d:). Only the cache files have any effect on the speed of loading a particular instrument once the cache has been created (by the "first time" load or after you have made some change which needs the cache to be recreated). HW has facilities to set up and reconfigure the disks used (the reconfiguration preserves the content) The 4.1.1 manual describes what to do on page 25 in the section "changing installation locations".
I had also loaded some organs into other configurations which I no longer wanted, and so I navigated to the cache folder for the particular configuration and deleted the cache files. I suspect this is not a "supported" activity - you just need to confident that you are deleting the cache file you intended to delete.
Iain