I discovered something odd just now...
If I run the game fullscreen initially, it loads fast, but takes forever to quit.
Also, if I start the game in fullscreen, but switch to windowed mode, it takes forever to make the switch. But it will then toggle back and forth quickly and exit quickly.
However, if I run the game in a window initially, it loads fast, and it exits fast.
And finally, if I run the game in a window initially, then toggle to fullscreen, it takes forever to switch to fullscreen, but once fullscreen it will exit fast and toggle back and forth between windowed and fullscreen fast.
If I run the game fullscreen initially, it loads fast, but takes forever to quit.
Also, if I start the game in fullscreen, but switch to windowed mode, it takes forever to make the switch. But it will then toggle back and forth quickly and exit quickly.
However, if I run the game in a window initially, it loads fast, and it exits fast.
And finally, if I run the game in a window initially, then toggle to fullscreen, it takes forever to switch to fullscreen, but once fullscreen it will exit fast and toggle back and forth between windowed and fullscreen fast.