On my 2013 27" iMac I'm noticing when playing back music in iTunes that many of the tracks have an occasional pop sound. The pops are in the exact same spot when playing the tracks over again so I'm thinking the AAC files are getting damaged. I have iTunes match so I'm able to download a fresh copy of all my tracks and they sometimes are pop free, other times the replacement track from iTunes Match has new, different pops. I'm worried my Hard Drive may be having problems. Is there anything I can do as far as a test to see if there is a hardware issue? The iMac is a 27" 2013 base model with a 1TB Fusion Drive.