You can go ahead and buy the new drive. These new technologies are made to be backwards compatible inside of this class. If not, there would be some kind of warning or caution that would be published. Case in point, when they went to the newer type of AGP cards they had to give a warning that there was a voltage problem with the older AGP slots. Of course, that had nothing to do with hard drives. The three major categories of hard drives are the original parallel interface, the new serial interface, and a type of interface that we call the SCSI.