Extremely Slow iMac Performance

[dmw16]

I have a 27" iMac (2.7Ghz i5, 20GB RAM) and over the last 6 months its performance has been terrible. The hard drive sounds like it's constantly searching and even things like FireFox are painful to use and have frequent thinking-pinwheel moments that can last up to a minute before it comes back to life.

The drive's SMART status shows good and I am not one of the serial numbers covered under the 1TB Seagate recall. I did some health checks on my drive last week and it found errors that it seems to have been able to fix, but now it's back to its old ways.

I am running another drive scan and I'll share the results here, but has anyone else had issues with their iMac?

UPDATE:
Disk scans reveal no issue.

 

[cheez]

Please try Cheez's Solution:

- Download and run APPLEJACK. This is a really good prog. This will clear up a lot of system performance issues.

- Clear all history / cache from Firefox menu.

- Make sure you have enough free disk space available. If it takes up 90+% it will run into some issues.

 

[dmw16]

Thanks. I still have 300GB of my 1TB of space left. I have thought about switching to a SSD and just getting an external thunderbolt drive for my larger files, but I'll try applejack first.

 

[dave_the_nerd]

Yeah.... it still sounds like a bad HD. If you can actually hear the HD crunching in a relatively new iMac, something is up.

I'd probably replace it out of principal. But you shouldn't not buy an SSD if you're going to do that.

 

[aaksheytalwar]

Could be a bad HDD.