mac USB ports
I have a late 2013 iMac which has been updated with all the latest software. I am sure that the USB ports which are advertised as USB 3 are not USB 3 at all. When I attach an external hard drive via USB 3 to back up my laptop running windows 8.1 the speed is blisteringly fast. When I do the same with my mac it is slower than a snail on valium. Is this normal? Am I doing something wrong? Please help. Thank you
iMac (27-inch, Late 2013), OS X Mavericks (10.9.4)