I have the "reopen folders" option disabled.

So when poser starts (3 seconds), the library opens with nothing open. Each folder which I open fills iimmediately. If I have a very large folder (800 sub folders) and scroll to the bottom and open a subfolder there, it takes 2-3 seconds to fill the new folder.

If you have reopen folders enabled, the library will go through all open folders and that may take a long time if you have a large number of them open the previous time you used Poser.

I use the air version because I like ability to minimize it to the task bar