USB 3.0 RPM speed?

Solution
https://www.amazon.com/Book-Desktop-External-Drive-WDBBGB0040HBK-NESN/dp/B01LQQHL4E/ref=sr_1_4?s=electronics&ie=UTF8&qid=1514303930&sr=1-4&keywords=usb3.0+wd+4tb

That's an example of a desktop, 3.5" HDD... I don't think they tend to be 7200RPM usually.

If you definitely want 7200RPM you may want to buy the HDD and USB3.0 enclosure separately. IMO the speed doesn't matter that much unless you are gaming or otherwise constantly needing fast transfers.

This SEAGATE is 7200RPM, 3.5", 3TB:
https://pcpartpicker.com/product/j28H99/seagate-barracuda-3tb-35-7200rpm-internal-hard-drive-st3000dm008

My Seagate USB issues where not due to the HDD itself but rather the power adapter, cable, and the electronics in the case (yep, all THREE things...
RPM - Revolutions Per Minute
Is a measurement used for Hard Drives only.

SSD's and USB thumb drives use memory chips not spinning disks.
Both are faster than a hard drive.
A USB 3.0 thumb drive will likely serve your purpose. What are you planning to use it for?
If you were planning on getting a USB 3.0 hard drive instead then you SHOULD opt for the 7200RPM drive but it will not be nearly as fast as a SSD.

USB 3.0 speed is maxed out at 625 MB/s which is a transfer rate that is faster than any spinning disk can handle.
 
USB2.0 in practice for external devices maxes out at almost exactly 32MBps.

USB3.0 in practice is bottlenecked solely by the HDD itself and what data is being accessed (smaller pictures files could be closer to 2MBps). Max speeds for larger, sustained transfers could be over 130MBps.

Other:
I've had a lot of issues with SEAGATE, and investigated and IMO (I could be wrong) Western Digital has better USB drives.

*So choose a drive that:
1) uses USB3.0
2) is 7200RPM (if you know)
3) capacity fits your needs/budget (2TB?)
4) Size fits your needs/budget

2.5" is slower but more portable. A 7200RPM 2.5" drive is slower than a 3.5", and the average speed of a LARGER capacity drive is also higher... that's due to the rotational speed of the OUTER EDGE of the drive platters...

The data is more likely to be on the outer edge if you have more capacity, and 3.5" has a larger diameter so it travels faster (at same RPM).

OTHER:
WD also makes a great WDMYCLOUD device if you want it just for the home. It attaches to the ROUTER via Ethernet cable and becomes accessible to all wi-fi or ethernet media/PC devices... I use it to stream MOVIES.

It's fast (up to 90MBps).

SUMMARY:
Your choices should be:
a) USB3.0 2.5" (portable)
b) USB3.0 3.5" (semi-portable)
c) WDMYCLOUD (local; all devices)

3.5" HDD's tend to have AC adapters as well, whereas 2.5" HDD's do not.
 
*I forgot to say that there are XBOX ONE specific HDD's that are 3.5" but don't have the AC adapter.

(You don't need the AC adapter if using USB3.0 and the drive is designed to get power that way, but they include 3.5" HDD's for desktops because using USB2.0 connectors would cause problems.
 
https://www.amazon.com/Book-Desktop-External-Drive-WDBBGB0040HBK-NESN/dp/B01LQQHL4E/ref=sr_1_4?s=electronics&ie=UTF8&qid=1514303930&sr=1-4&keywords=usb3.0+wd+4tb

That's an example of a desktop, 3.5" HDD... I don't think they tend to be 7200RPM usually.

If you definitely want 7200RPM you may want to buy the HDD and USB3.0 enclosure separately. IMO the speed doesn't matter that much unless you are gaming or otherwise constantly needing fast transfers.

This SEAGATE is 7200RPM, 3.5", 3TB:
https://pcpartpicker.com/product/j28H99/seagate-barracuda-3tb-35-7200rpm-internal-hard-drive-st3000dm008

My Seagate USB issues where not due to the HDD itself but rather the power adapter, cable, and the electronics in the case (yep, all THREE things failed)... I ended up taking out the HDD to put in my computer.
 
Solution