Experienced pc hardware guy here. But not all that much on the software side. I get a lot of new music and am constantly updating my music library of about 70gb of mp3's. I like to back up the music folder on a usb drive periodically, and do this in windows explorer by the simple "copy and paste" method...and it takes about 40 minutes...most of this time is spent reduntantly re-writing most of the pre-existing mp3 files. Is there a better way (or cool software program or utility) to do this so that only the updated files are written to the usb drive? Any help much appreciated.