When I leave iPhoto open for extended periods (which i'd like to do most of the time) it seems to hit the HDD pretty hard, constantly, slowing some stuff (particularly time machine backups!) considerably. I'm on an '08 imac, 2.8ghz, 4GB ram, 8800GT.. Snow Leopard.. It runs fine other than that.. I do have a 42GB library, 246 of the files are movies. A lot of the photos are RAW.. Anyone experienced similar? And is there some way to stop it?