The ST4000DX000 are 7200RPM. But thats not what makes them great. They have TLER which makes them perfect for NAS.
Why I am posting this is not for External drives but for the 4TB internal XT drives that are in these cases. Most of the external drives now have the ST4000DM000 Drives which are
5900RPM. But there are plenty that have XT. How do you tell... which cases have what...?
Pl. see the attached pics.. If it has the Windows 7 logo... it has XT drive. If it has Windows 8 logo... it has DM drive. I bought 11 of them.. and found XT drives in each of those windows 7 logo boxes.
Icing onthe cake. 2 yr warranty from costco. And the drives themselves have 3 yr warranty.
These are still selling for over $240 elsewhere.