I use Ubuntu 12.04.
I have a good PC , a Dell XPS, with 8 GB of memory and a 1TB HDD and an i5 processor.
When I copy files internally (to and from the internal HDD), nautilus initially shows speeds of about 30 Mb/s. But, the problem is, it always, keeps dropping by 0.1 Mb/s at a time (every 5 seconds or so), till it stabilizes at around 1Mb/s (if the copying isn't finished already).
I'm trying to backup my PC into a 1TB WD My Passport external HDD (USB 3.0). It started at 36 Mb/s and is now 8Mb/s in 15 minutes and still falling regularly. I have around a 100 GB of data to copy and it doesn't seem it will happen.
Any ideas about the problem?
While I couldn't really find out what caused th problem, using a tool like
rsync helped and it is much faster than the traditional
Sebastian Werk's answer helped too, but it doesn't tell what caused it.