I am doing a TM backup for the first time to a portable disk from my macbook Pro(mid 2010) over a firewire connection (both ends). The disk only contained a folder of around 20GB of manually backed up stuff before I decided to TM to it (left the folder). Now it's only done exactly 580MB in 30 mins (around 19.33Mb/min) is this normal?
Turns out that the problem was that the disk wasn't empty. Formatting the disk and starting again solved the problem.