If you're using any version of Windows, one of the biggest problems, even today is the slow speed of copying files. I experience this just a few days back when trying to clean up my external hard disk on Windows 8.1.
You have this whole stack of movies safely stored on DVDs. You could run into two issues. The DVD gets scratched and you lose your precious movie The DVD is for a specific region and your player doesn't support it If you have sufficient hard disk space, then you can store the DVD on your disc and always burn it out in fresh.
7 Super Tools For Faster Windows File Copy / Move Process takes a look at five freeware and two shareware programs that will help speed up the copying / moving files. Extremely useful when you are moving tonnes of large files.