The two hard drives purchased from Amazon I have been going on for several months. There are quiet and reliable hard drives. Using Backup Disk Image 5.5 of the Berlin company O & O I have the operating systems (C-system disks) my two computers bootable copy on the new disks, and then replaced the old C-disks with the new. In order for the data security of both my computer is backed up again. Both computers started with the new hard drives safely and quickly. The many programs that were installed on the old hard drive to work with the new drives even better and faster. I had to install a single program. Everything works fine. Immediately after the exchange of the hard drives I have the very large backup files of my D-disks stored with the same program DiskImage 5.5 on the new disks. The validation (checking the stored backup file) was positive in both cases. All sectors of the new disks are free from defects. The CHKDSK program of the same program brought only positive messages. My C-system disks contain only the operating system and the installation of my quite many major programs. On the D-Disk I save only the results of the work with my programs. I can always replace each of the two hard disks without data loss. With the same assurance program DiskImage 5.5, I then created my backup files C-system disks and stored on the D-Disk. Chkdsk and validation were positive again. I may at any time the contents of the backup files in a virtual drive F: transfer and new ESet secure or error free from here every single file. That's easy to look even without the help file of the program. I am very pleased with the two new 1TB hard drives the company Western Digital. Therefore, both disks get my special recommendation.