It is bringing Aperture to its knees. I'm on a 2GHz Core 2 Duo MacBook and have 2GB ram. I want to keep the files as 134mb tiffs for archival purposes, but i DONT want Aperture to display the 134mb files when i'm browsing through. What's the point of spending all night "processing previews" if the program doesn't even bother making use of them??? i mean, this is just ridiculous. just changing the metadata takes 5-10 seconds to process.