External hard drive connected to iMac 5K Retina is suddenly extremely slow - looking for feedback/advice

[abmaj9]

Hi, my main computer is an iMac 2017 5K Retina. I've noticed my WD external HDD has been running slower lately so I wanted to check if something's wrong with it.

I just learned about Blackmagic Disk Speed Test and downloaded it to test the speed. First part of question: for anyone who is familiar with this tool, about how long does it need to run to give an accurate reading of the drive? I've been running it about 20 minutes, not sure if that's long enough.

Second part of question: what's an acceptable range (or minimum acceptable speed) of mb/s for an external hard drive's read & write speed performance when connected to an iMac? If it's relevant, this Mac has a 4.2 GHz i7 processor.

I attached screenshots of my iMac's SSD report and of the WD 5TB HDD report. Of course I expected a big difference...but...this big??

Thanks for any advice on this

 

[MevetS]

The first thing you should do, and hopefully have already done, is backup the drive. Super Duper and Carbon Copy Cloner are apps you can use to do this. You’ll of course need another drive to backup to. Drives are relatively inexpensive and you should be able to find Black Friday deals (depending on where in the World you are).

In the Applications > Utilities folder on your Mac there is an app named Disk Utility. Run that and see if it reports any errors. It may be able to fix any it finds.

I can’t answer your question about the disk speed test. Unfortunately it may be time to replace this drive.

Good luck.

 

[Fishrrman]

HOW OLD is the WD drive?

I agree with Mevet.
Time to get ANOTHER drive (as quickly as you can), and use a cloning app to get what you can off the WD drive before it fails completely.

For a platter-based hard drive:
I would suggest that you buy SOMETHING OTHER THAN WD this time.
I prefer Toshiba and Hitachi (HGST) myself.

I'd suggest the 2.5" size, rather than the 3.5" size.

Do you really need 5tb?

 

[ght56]

I also agree. You need to back this drive up immediately.

Your iMac has a different type of drive called a solid state drive, whereas the WD uses a hard disk drive. Major speed differences are normal, but the WD should be somewhere in the ballpark of 40 to 140 MB/s depending upon the connection used and how full the drive is. The speeds you posted are extremely concerning. This can suggest the hardware may be failing. Alternatively, it may also suggest some type of directory corruption. Either way, you want to be sure anything on the WD drive is also stored on another drive as it may become unreadable or fail in the near term future.

How old is the WD drive and how filled up is it?

 

[lowendlinux]

Check your HD