Needs some advice with someone that has some experience with this.

I have a Western Digital My Book 4TB External Hard Drive about 2 months old that is not performing well, what I have noticed is that the performance drop happens when the Active time (reported by Windows 10) goes to 100%.

ISSUE: When the Drive Active time is around 30% I get about 120MB/sec, when the Active Time is 100% I get less than 1MB/sec.

What's using the drive:

  • I have some vhd's on the drive

What I've done so far to troubleshoot

  • I've checked the processes using the drive and it is the vhd's that I expect using it
  • The vhd's are not using the drive that much to cause a 100% active time
  • I'm using Windows 10 Pro and it is set to High Performance power options
  • I've checked S.M.A.R.T values and they are fine

Here is Windows showing 100% Active Time enter image description here

Here are the processes when the drive is at 100% Active Time:

enter image description here

Here are the processes when the drive is at around 30% Active Time:

enter image description here

Here is S.M.A.R.T information on the drive:

enter image description here


If you have multiple VHDs being accessed at the same time a single drive your performance would drip to a horrendously slow rate every time. If they files being accessed are small, say under 1MB, if would get painfully slow. Especially if the files are split evenly over the drive due the VHDs being non-fragmented.

This site shows a 1TB drive under a 4k random R/W load at 330k/sec at 82 IOPS. I assure you, newer consumer drives at the same RPM are going to have a similar throughput and this is inline with what you are expirienceing

Use a disk benchmark program to test your drives random 4k throughput to give you an idea of its capabilities.

Then, troubleshoot what is thrashing your HDD and implement a solution. I would recommend installing an SSD for your highers IOPS VHDs.

  • although the performance is very disappointing at the moment since I have no other explanation and your link shows similar results I would have to conclude the drive has reached is limitation. There are cases were some of the VHDs I'm using are getting lots of small reads and writes. Thanks for taking the time to reply. – Exocomp Jul 25 '17 at 15:29

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