Hard drive (HDD) access has become very slow at times 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?
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.