Is the Lite On LDW-851SX External the same drive as the Lite-On LDW-811S but just a external? I am looking for a drive to copy my dvd movies and also backup my pc games. Many have the safedisc protection. The LDW-811S review make it look like a good choice but I want a external drive and all I can find external is the Lite On LDW-851SX model. Thanks for any help you can give.