I have an 8GB USB thumb drive. When I copy files to/from it to my Mac Pro (Early 2008 2.8Ghz), the transfer speeds are very slow. But when I use it with my 2009 Macbook, the speeds are fast. Why would it work faster with a low end Macbook than with a Mac Pro? I'm using one of the USB ports on the front of the Mac Pro. I have fairly fast 750 GB and 1 TB drives in there.