Very Slow cloning... Help!

I have been using Acronis to clone hard drive images on Toshiba laptops without a problem. I was using ATI 2009 and using a usb boot media and an external USB HDD with the image I have to clone. An image took all of about 20 minutes to complete.

Now I try to clone a new Samsung laptop, which has exactly the same HDD speed (although the make is different) as the Tosh (5400rpm) and although the layout of the partitions on the HDD is different, the actual amount of data to clone is less than on the Toshiba's. However it is painfully slow- about 2 hours to complete. I googled the problem and read that an upgrade may sort it out and so I upgraded to ATI 2010. Still exactly the same problem.

The USB external HDD is exactly the same one as previously used reformatted with a Samsung image on it.

I have no idea why it is taking this long- surely with less data to clone it should be quicker?
Anyone have a solution as to what may be causing the imaging process to be so slow?