Apple iMac 20" / MODEL A1224 / EMC # 2210 / Very Slow

If you are seeing slow performance and the Apple Hardware Test generated an error then your hard drive may be generating an increasing number of read/write errors. I suggest downloading a copy of Smart Utility from Volitans software in order to pull the SMART (Self Monitoring, Analysis, and Reporting Tool) log files from your hard drive. If the results indicate that the drive is failing or has failed then back up your data immediately and make arrangements to replace the hard drive.

http://www.volitans-software.com/smart_utility.php

Make a "Genius" appointment at an Apple Store, or go to another authorized service provider.

Back up all data on the internal drive(s) before you hand over your computer to anyone. There are ways to back up a computer that isn't fully functional — ask if you need guidance.

If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.

Keeping your confidential data secure during hardware repair

*An SSD doesn't need to be zeroed.

Reading the SMART data will do you no good whatsoever.

Linc- I disagree with your opinion on SMART data.

SMART logs may not predict potential HDD failures with 100% accuracy,but they do provide a good picture of the hard drive's current health. No tool is perfect, but If the SMART logs show a large number of pending or reallocated sectors then it's probably safe to say that read/write errors are a big contributor to the performance issues being reported by Friendly_help_seeker. If the SMART logs are clean then there may be other issues at play that may explain the slow performance. In my experience working with thousands of systems over the years I have found the SMART logs, and espeically the pending sector counts to be an excellent troubleshooting tool. Google's hard drive study done several years ago backs this up, showing that drives with scan errors are ~10X more likely to fail than drives without errors. The same trend is reportedly true for drives with reallocated sectors.

Now to answer 'Friendly_help_seeker's.' Hard drives do wear out, so the best recommendation I can make is to make sure you always have a backup of your data. Based on the model iMac you have it looks like your system has had a relatviely long life. I personnally use a Time Capsule for a continuous backup, and also keep a copy of my data on a separate external hard drive that I keep in a safe location. Every 1-3 months I make a new backup to this external hard drive. It's not always current, but in the event that my Time Capsule and iMac were both lost or stolen I would at least have access to most of my data and the priceless photos of my kids.

The hard drive in my iMac began acting up last year and I couldn't explain why until one day when I saw my kids playing with a rubber ball inside the house. They had been playing four square inside and the soft rubber ball kept hitting the iMac. Hard drives don't like to be jostled while they are spinning. In my case the SMART data showed several bad sectors which I suspectoccurred when impacts from the ball caused the read/write heads in the hard drive to briefly impact the media surface leading to irrepairable damage. Needless to say, my kids no longer play four sqare near the iMac.

Whatever the resolution is, I would appreciate if you share how your issue was ultimately resolved. Good luck.