Multiple USB WD drives - only 1 is very slow - any ideas?

I have multiple USB Western Digital drives. Whilst copying only 1 is performing bad.
Whilst copying to other WD drives the speed is roughly 140-145MB/s, the drive in question has a max of 38MB/s
Copying the same type of files (4.x GB .iso)

The drives obviously rely on WIndows drivers, they are up to date.
Chkdsk says : no errors
There is enough empty space on the drive.
I have tried 3 different USB ports: makes no difference.
Slow one: SATA 600
"Fast" ones (well, 'fast'... fast compared to the slow one) SATA300

Does anyone out there have a clue?

Thanks.



(latest version of Windows 10 x64)

Megahertz said:

The drives are SATA 600 and they are installed on a USB case?
If yes, it could be the case or the drive that is slow.
You should test the drive connecting them to a SATA port inside the computer.

Chkdsk only check the logical structure of the drive, not the hardware.
Download extract and run CrystalDiskInfo. It's a portable. Doesn't need to install.

They are external Western Digital USB Drives, the slow one is a WD 8TB MyBook.

Have you tried different cables? The low speed sounds a lot to USB2 instead of 3. USB3 uses additional wires. I once had to replace the original cable of an external drive (although my problem was different, I had flaky connection).

MisterEd said:

What model drives and external cases are you using? How full are the drives and have you checked to make sure they aren't fragmented? A highly fragmented drive will greatly decrease it speed.

Over the years I have had a numbers of external cases. They supported SATA 1 (150MB/s), SATA 2, (300MB/s, and SATA 3 (600MB/s). The same goes for enclosures. The drives speed is limited by the slowest speed supported by either the drive or its enclosure. The external drive is also limited by whether its has USB 2.0 or USB 3.0.

To illustrate why I am asking these questions here are the results when different drives and enclosures are used:

This is what I could pull out on details regarding the drives

JLArranz said:

Have you tried different cables? The low speed sounds a lot to USB2 instead of 3. USB3 uses additional wires. I once had to replace the original cable of an external drive (although my problem was different, I had flaky connection).

Thanks for tip.

Yes, different cables and different ports.
No difference, regretfully so.
Strange thing and probably I have to live with it.

Over the years I purchased a number of WD external drives.
All drives show a healty temperature of some 40, 43, 45 degr.c. as max.
This drive, even idle shows 50 degr.c. at just 5400 rpm
No SMART errors.