I had the same kind of problems (working with video files of around 1GB each, plus photo files, plus audio files, etc.)
The problem disappeared when I put files are on separate, fast-access, USB keys (for example Patriot). I tried the following configuration: videos on one USB key, and other files (projects (.osp), music, pictures/photos, sequence of pictures) on another. With that configuration, everything worked fast, almost instantly.
This indicate that the issue might be some traffic jam when the programs has to access several files, some of which are big, at the same time (or in a short period of time), on the same media.
I had the same kind of problems (working with video files of around 1GB each, plus photo files, plus audio files, etc.)
The problem disappeared when I put files are on separate, fast-access, USB keys (for example Patriot). I tried the following configuration: videos on one USB key, and other files (projects (.osp), music, pictures/photos, sequence of pictures) on another. With that configuration, everything worked fast, almost instantly.
This indicate that the issue might be some traffic jam when the programs has to access several files, some of which are big, at the same time (or in a short period of time), on the same media.