I have a mid-2011 iMac with a 7200 rpm 2‒Terabyte HDD, from Hitachi.

The last year, I have increasingly been noticing a behaviour where access to the hard drive has become slow – especially since around the time El Capitan was released.

I notice this behaviour chiefly in two situations:

  • Application installs are slow, and/or sometimes seem to freeze – being stuck at "1 second left" for several minutes.
  • Finder is frequently slow to populate the contents of folders, like /Applications and a spinning wheel for 30 seconds. Other times, Finder is snappier and population times are adequate.

As such, the performance strikes me as inconsistent, making me suspicious of a burgeoning hardware failure. However, I do not hear any weird noises from the drive, and Disk Utility results seem OK.

The system has, of course, experienced increased demands since purchase. Besides running a more modern OS, I also make heavy use of Dropbox whose initial boot indexing process requires a lot of work for the drive; and I also have a Time Machine that is frequently backing up lots of media. Spotlight and Alfred also seem to weigh down a bit some time after system startup, as well as antivirus programs I have had installed (not at the same time) such as Avast and Sophos Antivirus.

On the other hand, I can't see that these applications are always active when I encounter drive performance issues.

Is this drive performance to be expected with a five-year old HDD drive given these demands – or do the performance inconsistencies signal hardware problems?

1 Answer 1


Before even looking at anything else...
Two antivirus apps on one machine is not good; they fight each other.
Avast is also known to be cripplingly slow, with Sophos not faring much better.

AV-TEST is the closest to an actual 'authority' on the subject. Have a look at their recommendations.

I would lose both those antivirus solutions, then test again temporarily without any AV.

  • Sorry to be unclear – I haven't had them installed at the same time. I switched from Avast to Sophos and that gave a slight performance increase, but not by much.
    – P A N
    Aug 28, 2016 at 9:55
  • Yup - you just went from the slowest to the 2nd slowest - I'd still test with neither. Anecdotally, I can perceive the hit that both of those give - on a Mac Pro 3.46GHz dual Xeon & 1TB SSD
    – Tetsujin
    Aug 28, 2016 at 9:55
  • You were right about the AV. I tested out a few, and the only one that gave me adequate performance was BitDefender, but not having any at all is probably better. Even with BitDefender, the computer is now snappier than before. It's still slow to populate folders some times – much worse than when I purchased the iMac in 2011 – but maybe the simple fact is that a 7200 rpm drive is old technology for today's OS?
    – P A N
    Sep 2, 2016 at 20:42
  • I never looked back once I put SSDs in all the machines here. Breathes new life into everything.
    – Tetsujin
    Sep 3, 2016 at 5:26

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