Are there any solutions to 5 hour downloads of a 1.5Gb movie when you have DSL operating at 5Mbit/s?

I've had movies download in half an hour, but the last two times I've downloaded a movie it has taken up to 5 hours to download an SD version. We'd start to watch the movie after it has been downloading for an hour but would have to take about 5 - 10, 10 - 15 minute "breaks" while watching for the movie to download enough so we can watch another few minutes of the video.

Is this due to the time of the week/ night that we download. I've have tested my download speed while the downloads are occuring and we are getting 5.83Mbit/second.