when I try to open many images, maybe several hundret, it takes Gigapixel ages to complete even loading them. The Windows 10 task manager does not even show any progress in terms of memory usage. I think my Intel 8700K and 32 GB or RAM as well as an M.2 SSD is not that slow. What is going wrong there?
Computers use Virtual RAM as an aid to the real RAM. You probably have “flooded” Virtual RAM (the Paging file), and pooled so many resources into Gigapixel that you have simply given your poor computer too much to do.