DSchro Multiple cables isn't going to help if none of them are good cables. Have you tried a good cable -- one from a recognized brand, with a good speed rating? It's not a bad idea to have a good power rating too -- in theory that's irrelevant, but in practice a cable with a good rating for both from a reputable manufacturer is most likely to work out.
That said, as long as progress is continuing it's ok to let it run. What's not good is if it progresses well for a while and then comes to a stop.