iMac is really slowing down

There are 3rd party programs of course, but what I would suggest is the following.

(Use the spotlight search to find Disk Utility quickly)

Verify Disk and Repair Disk Permissions in Disk Utility.

If it still goes slow after Repairing Permissions and Verifying Disk, try:

Boot up into Safe Mode

http://support.apple.com/kb/HT1455

Any Luck?

Actually, your iMac is a 2010 model if it has a 3.06 GHz CPU.

Do you run any kind of AntiVirus software?

Open OS X System Preferences Pane. Locate and click on Accounts.

A Window should open. On the left select or click your user account. On the right click the Login Items tab to see if there are a lot of background apps or processes running in the background at startup.

Also, in your Home folder/Applications Folder, locate the Utilitites Folder. Open this folder and look for the Activity Monitor app.

Launch this app and look at all the processes running to see if you can see one or more processes that are taking up a large percentage of your CPU power.

First, back up all data immediately, as your boot drive might be failing.

A possible cause of a slow user interface is a large set of image or video files on the Desktop with preview icons. If you have more than a dozen or so such files, move them to another folder.

Another possible cause is iCloud activity, especially Photo Stream synchronization. If applicable, uncheck all boxes in the iCloud preference pane and see whether there's an improvement.

Otherwise take the steps below when you notice the slowdown.

Step 1

Launch the Activity Monitor application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad. Click Utilities, then Activity Monitor in the icon grid.

Select the CPU tab of the Activity Monitor window.

Select All Processes from the menu in the toolbar, if not already selected.

Click the heading of the % CPU column in the process table to sort the entries by CPU usage. You may have to click it twice to get the highest value at the top. What is it, and what is the process? Also post the values for % User, % System, and % Idle at the bottom of the window.

Select the System Memory tab. What values are shown in the bottom part of the window for Page outs and Swap used?

Next, select the Disk Activity tab. Post the approximate values shown for Reads in/sec and Writes out/sec (not Reads in and Writes out.)

Step 2

If you have more than one user account, you must be logged in as an administrator to carry out this step.

Launch the Console application in the same way you launched Activity Monitor. Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left.

Select the 50 or so most recent entries in the log. Copy them (command-C) to the Clipboard. Paste (command-V) into a reply to this message. You're looking for entries at the end of the log, not at the beginning.

When posting a log extract, be selective. Don't post more than is requested.

Please do not indiscriminately dump thousands of lines from the log into this discussion.

Important: Some personal information, such as your name, may appear in the log. Anonymize before posting. That should be easy to do if your extract is not too long.