Why Would My Mac Suddenly Run Slow?

Nokomis wrote:
For two days now my Mac is just "crawling." I haven't added anything.

I'd launch the Activity Monitor utility, set the list at the top to "All Processes", click on the "% CPU" heading until the top CPU users are at the top of the list, then see what's consuming CPU time.

See:

Mac Maintenance Quick Assist,
Mac OS X speed FAQ,
Speeding up Macs,
Macintosh OS X Routine Maintenance
Essential Mac Maintenance: Get set up,
Essential Mac Maintenance: Rev up your routines,
Maintaining OS X,
Five Mac maintenance myths, and
Myths of required versus not required maintenance for Mac OS X for starters.

I also suggest updating to the latest. Check via Software Update. You're woefully behind the curve with 10.6.2.

Nokomis wrote:
This is what I saw when I went to the Activity Monitor...

% Idle = (Upper 90s)

Your Mac is definitely not slow because of too much CPU activity. I'd follow baltwo's advice to investigate other possibilities. You might also launch Disk Utility, select the boot drive ( not the boot volume), then look at the S.M.A.R.T. status at the bottom to rule out the possibility of a failing disk.

Nokomis wrote:
I did go to Disk Utilities but it was way over my head

What I asked you to do should be relatively easy and risk-free. Launch Disk Utility. In the left column select the first item. Look near the bottom of the window for something labeled "S.M.A.R.T. Status". For a disk drive in good condition the value after that should be "Verified" Now you can quit Disk Utility.

Nokomis wrote:
It did say VERIFIED.

Then you can also rule out an impending disk failure as an explanation of your Mac's slowness. That still leaves you with baltwo's advice.

Another standard thing to check is how much free disk space you have - at least 15% is generally accepted as necessary for the Mac OS to work properly.

charlie

888 MB.

Is that the free space? That looks very small. How big is the drive? (We need to look at what percentage of the total is 888 MB).

One way to get this information is to find your disk drive icon (originally called Macintosh HD, and select "Get Info" from the File menu (command-i). There you will see "capacity" (this is the total size of your disk) and "available" this is the amount free (probablly the 888 MB).

charlie

Message was edited by: CT

If that's the case, you should be getting a warning pop-up that your free space is too low. If you continue running like that you are skating on thin ice and there may be severe directory corruption which will really mess things up. You need to delete or empty things out onto an external drive.

Make a bit of room first and then get OmniDisk Sweeper to see where space is being used. Don't start deleting anything yet.

http://www.omnigroup.com/products/omnidisksweeper/

Well, kinda....

The iMac 8,1 should have hundreds of GB of hard disk space, I believe. So if you only have about 900 MB free you definitely should benefit from deleting files to make more room on you hard disk.

charlie