iMac is SLOW.

Uninstall the "clean up" software and see if that improves things.

How To Uninstall CleanMyMac 2?

Also try un-installing RIM as that sometimes causes problems. Use the developer's un-install instructions.

Activity Monitor - Mavericks also Yosemite

Activity Monitor in Mavericks has significant changes

Performance Guide

Why is my computer slow

Why your Mac runs slower than it should

Slow Mac After Mavericks

Things you can do to resolve slowdowns see post by Kappy

DO NOT USE ANY SO CALLED APPS CLAIMING TO "CLEAN", "OPTIMIZE" OR "SPEED UP" YOUR MAC!!!! EVER!!!!

Apps like MacKeeper or any other maintenance apps like CleanMyMac 1 or 2, TuneUpMyMac, SpeedUpMyMac, MacCleanse or anything like these apps, installed on your Mac, while they appear to be helpful, can do too good a job of data "cleanup" causing the potential to do serious data corruption or data deletion and render a perfectly running OS completely dead and useless leaving you with a frozen, non-functional Mac.

Plus, these type of apps aren't really necessary OR needed. They really aren't.

There are manual methods to clear off unnecessary data off of your Mac that are safer and you have complete control over your Mac and not just leave a piece of auto cleaning software in charge of clearing off data off of your Mac. Their potential of causing OS X issues outweighs the implied good and benefits these types of hard drive or memory "cleaning" apps are written to do.

These types of system 'cleaning" apps are very poorly written and are really a scam to rob newbie and novice Mac users of their hard earned cash for a poorly written maintenance program that will do much more harm to a perfectly normal running OS X system than the good that the app developers purport these types of apps will do.

Plus, the software companies that write these apps make it hard to easily uninstall these apps if something DOES go wrong and these apps work in a way where you have no recovery or revert function to return your Mac back to its former, working state in the event something does go wrong.

It is best to never, EVER download and install these types of apps.

The risk to your system and important data is too great a risk!

Your hard drive free space is getting to the point where you should start considering doing some manual housecleaning to try and regain some additional space on your hard drive.

Here are some general tips to keep your Mac's hard drive trim and slim as possible

You should never, EVER let a computer hard drive get completely full, EVER!

With Macs and OS X, you shouldn't let the hard drive get below 15 GBs or less of free data space.

If it does, it's time for some hard drive housecleaning.

Follow some of my tips for cleaning out, deleting and archiving data from your Mac's internal hard drive.

Have you emptied your Mac's Trash icon in the Dock?

If you use iPhoto or Aperture, both have its own trash that needs to be emptied, also.

If you store images in other locations other than iPhoto, then you will have to weed through these to determine what to archive and what to delete.

If you are an iMovie/ Final Cut user, both apps have their own individual Trash location that needs to be emptied, too!

If you use Apple Mail app, Apple Mail also has its own trash area that needs to be emptied, too!

Delete any old or no longer needed emails and/or archive to disc, flash drives or external hard drive, older emails you want to save.

Look through your other Mailboxes and other Mail categories to see If there is other mail you can archive and/or delete.

STAY AWAY FROM DELETING ANY FILES FROM OS X SYSTEM FOLDER!

Look through your Documents folder and delete any type of old useless type files like "Read Me" type files.

Again, archive to disc, flash drives, ext. hard drives or delete any old documents you no longer use or immediately need.

Look in your Applications folder, if you have applications you haven't used in a long time, if the app doesn't have a dedicated uninstaller, then you can simply drag it into the OS X Trash icon. IF the application has an uninstaller app, then use it to completely delete the app from your Mac.

To find other large files, download an app called Omni Disk Sweeper.

http://www.omnigroup.com/more

Also, Find Any File

http://apps.tempel.org/FindAnyFile/

Download an app called OnyX for your version of OS X.

http://www.titanium.free.fr/downloadonyx.php

When you install and launch it, let it do its initial automatic tests, then go to the cleaning and maintenance tabs and run the maintenance tabs that let OnyX clean out all web browser cache files, web browser histories, system cache files, delete old error log files.

Typically, iTunes and iPhoto libraries are the biggest users of HD space.

move these files/data off of your internal drive to the external hard drive and deleted off of the internal hard drive.

If you have any other large folders of personal data or projects, these should be archived or moved, also, to the optical discs, flash drives or external hard drive and then either archived to disc and/or deleted off your internal hard drive.

Moving iTunes library

http://support.apple.com/kb/HT1449

Moving iPhoto library

http://support.apple.com/kb/PH2506

Moving iMovie projects folder

http://support.apple.com/kb/ph2289

Good Luck!

Upgrading to Yosemite will NOT solve your issues, it will just make them worse.

Upgrading an OS doesn't magically make all of your computer issues go away.

You'll still have all of these issues you have now and your Mac will run even slower than it does now.

Plus, you still have no real hard drive space left.

If you are reluctant to make all of these fixes and changes, your only option is to make a backup of all your important saved data, and erase your hard drive and use internet recovery mode and do a complete, clean install of your OS X first, reinstall all of your applications from scratch and then restore all of your data from the backup that you need to create.

OS X: About OS X Recovery - Apple Support

Okay!

Good!

You still need take some precautions with your next step. Upgrading to Yosemite.

Before embarking on a major OS upgrade, it would be wise, advisable and very prudent if you backup your current system to an external connected and Mac formatted Flash drive OR externally connected USB, Thunderbolt or FireWire 800, Mac formatted hard drive. Then, use either OS X Time Machine app to backup your entire system to the external drive OR purchase, install and use a data cloning app, like CarbonCopyCloner or SuperDuper, to make an exact and bootable copy (clone) of your entire Mac's internal hard drive. This step is really needed in case something goes wrong with the install of the new OS or you simply do not like the new OS, you have a very easy way/procedure to return your Mac to its former working state.