iMac very slow and runs HOT. fan runs almost constantly

Ways to help make a slow Mac faster

17 Reasons Why Your Mac Runs Slower Than it Should

Slow Mac Performance? This Article Solves It!

Fix slow start-ups in OS X | MacFixIt - CNET Reviews

How to fix slow shutdown and startup times. | MacTip.net

6 Easy Tips to Speed Up OS X Yosemite on Your Mac

Avoid using any third-party software that claims to clean up your computer. Usually this software does more bad than good. Furthermore, you don't need it. Note that all computers will become slower over time even under normal use. Experienced users typically erase the hard drive and do a clean install from scratch at least once a year or whenever installing a major OS upgrade. Of course doing so also means you must maintain regular and multiple backups.

Add more RAM or cut back on the number of concurrently running applications and utilities. Remove unnecessary software such as anti-malware and software that promises to clean your Mac. Check for runaway processes: Runaway applications can shorten battery runtime, affect performance, and increase heat and fan acti… Also see:

Pre-Mavericks

Open Activity Monitor in the Utilities folder. Select All Processes from the Processes dropdown menu. Click twice on the CPU% column header to display in descending order. If you find a process using a large amount of CPU time (>=70,) then select the process and click on the Quit icon in the toolbar. Click on the Force Quit button to kill the process. See if that helps. Be sure to note the name of the runaway process so you can track down the cause of the problem.

Mavericks and later

Open Activity Monitor in the Utilities folder. Select All Processes from the View menu. Click on the CPU tab in the toolbar. Click twice on the %CPU column header to display in descending order. If you find a process using a large amount of %CPU, then select the process and click on the Quit icon in the toolbar. Click on the Force Quit button to kill the process. See if that helps. Be sure to note the name of the runaway process so you can track down the cause of the problem.

The Ultimate Fix

Backup everything, erase the drive, reinstall OS X, and restore your data from the backup. Reinstall third-party software from original media/scratch.

Before we can really be specific you need to provide specific temps, as "uncomfortable to keep your hand on the top" is totally subjective and late 2009-2011 iMacs are known for "feeling" warm to the touch. Look for tools such as iStat Pro or other temperature monitoring apps. Once you have posted specific temps then we can give you an opinion if your machine is running abnormally warm or not.

The one glaring thing I see though is your computer appears to need more RAM, 4GB is considered the bare minimum to run Yosemite so I would recommend upgrading to 12 or 16GB and then see if the beach balling goes away. If you decide to upgrade the RAM only use high quality RAM as iMacs are very sensitive to RAM. Two vendors frequently recommended on this site are OWC (www.macsales.com) or Crucial.com. Your computer can install up to 32GB of RAM so you can see with only 4GB you are only at very low percentage of the machines capacity. When you had Snow Leopard installed, 4GB was fine but newer versions of OS X also have more features which also require more RAM.

Upgrading RAM on 2011 iMacs is incredibly simple to do. Here is a video that shows how:

http://eshop.macsales.com/installvideos/imac_mid_2011_mem/

I have had this problem FOREVER, was driving me crazy.

1) First thing I would suggest, especially for that year (I have a 2010) is to blow out the vents. I had never done this and there was a ton of black silty dust. Get compressed air. Blow out the round vent behind the stand, the vent along the top, the super drive and all the ports (usb, etc).

2) Reset the the SMC and the PRAM. Super easy, just takes a sec.

- shut down computer

- unplug all cords

- press and hold the power button for 5 seconds

- release power button

- attach power cord

- press power button

- BE QUICK - hold down the Command, Option, P and R (will take 2 hands) until computer reboots itself

- release the keys

I have bought from Data Memory Systems for a decade, at least...

http://www.datamemorysystems.com/apple-imac-intel-core-i5-quad-core-2-7ghz-27-mc 813ll/a-mid-2011-memory-upgrades/

Third from the bottom, two 8 gigabyte chips, DM50 229-1 x 2, $69.90...

Put a soft towel on a flat surface. Put the iMac on its face on the towel. Lift the foot, remove the three screws. There is no need to remove the current chips, just slide in the two new chips. Put the plate back. It should sit flush. If not, rotate 180 degrees. Tighten screws finger tight only. Done!

http://www.everymac.com/systems/apple/imac/imac-aluminum-faq/imac-intel-aluminum -21.5-inch-27-inch-how-to-upgrade-memory…

I would complete uninstall Cocktail and see how the computer runs. Sometimes third-party software can run up temps.

Never, EVER use compressed air to "blow" out dirt out of a iMac.

It will have just the opposite effect by just blowing/forcing more dust, dirt and lint into the inside of an iMac making it run even hotter.

For the record, Apple has no real procedures for really taking good care of your expensive Mac desktop or laptop.

It is as if Apple wants their products to fail in a predetermined time to force its users into buying their hardware products more often.

Apple's operating specs for the iMac, in my STRONG opinion, are NOT realistic and are designed to shorten the life of their computers by shortening their lifespan.

I had two older PowerMacs that were still going after 8 and 10 years, respectively. I bet if I setup my old G4 PowerMac today, that it would still power up and work like it did, just like it did the day I powered it down and put it away!

What can reduced the longevity of ANY computer and newer aluminum designed iMacs is basically too much internal or more than reasonable or excessive exposure to high internal temperatures.

Heat is the enemy of any electronics and, especially, micro electronics.

Apple designed a thin enclosure that, in reality, acts more like a portable oven or toaster that is basically "slow roasting", over time, the iMac's inner components. The rear of the iMac has been stated in various Apple conversations to act as a component to "draw away" or convect heat out of the inside of an iMac.

While some of this is true, in theory, the reality is the whole iMac box structure is all aluminum. Aluminum is a serious heat conductor/absorber, but has some abilty to conduct its heat out from the material, as well.

Unfortunately, the iMac's internal components generate more heat than the aluminum enclosure can conduct away and to the outside of the iMac.

There were never enough internal fans nor these fans spinning fast enough to keep an iMac, relatively, cool on the inside.

If the inside of the iMac fills up with dust and/or dirt particles and lint, the internal heat factor goes up considerably.

Once a year, I use a vacuum to vacuum ALL of my 2009 iMac's vents, slots, the various connection ports, the optical drive slot and the bottom air intakes and I remove the RAM module area metal cover and lightly vaccum inside of there. Basically trying to suck out as much loose dust, dirt and lint particles as possible.

I use the vaccum crevice attachment to very lightly move along my iMac so as not to both scratch or damage the outside finish and DO NOT USE ANY BRUSH attachments to cause any type of electrostatic discharge on anything on my iMac.

Unplug from power and disconnect everything from your iMac, first, before doing this.

Lay the iMac screen down on a soft toweling set down on a hard, stable surface before doing the vacuumimg procedure.

STAY AWAY FROM USING CANS OF COMPRESSED AIR, PERIOD!

This will only make the accumulated dust, dirt and lint situation worse!

Another thing I do to keep heat down is run a software fan control app to ramp up the iMac's internal fans to keep internal temps down.

The trick is to keep the fans running a little faster than what Apple has set, by default from the factory, but keep the fan speeds from being too fast so the fans act like internal vaccuums sucking into your iMac much more outside dust, dirt and lint particles at a much faster rate.

I, typically set my iMac's fans bewtween 1400-1600 RPMs and find that this is an acceptable increase.

I, also, use a small footprint, portable desktop fan that blows cool air around the hottest area of my iMac, typically the upper left rear of my iMac ( when facing the iMac's screen).

When really working my iMac doing illustration work, the temp of the CPU will rarely peak over 110° F and the hard drive temp is around 100° F and the GPU (which is one the hottest components in an iMac) I never let get hotter than 130° F.

Keeping your computer as cool as practically possible is what is going to keep it running well longer.

It would be great if you could make a YouTube video on how best to vacuum out your iMac - it sounds like it could save a lot of people from destroying their computers. Unfortunately, most of the videos online that address this problem show a compressed air solution.

It does make sense that you would want to get the dust out, but in my case (and I am sure for many others) it does clear the openings and allow sufficient air flow so the temperature goes down and the fan didn't run constantly. So while it absolutely solves one problem, it seems like it is creating another one.

Does that vacuum crevice attachment (would love to see a picture of one of these) allow you to reach the circular vent right behind the stand? Does a normal vacuum provide enough suction?

I used software to control the fan speed when it was running hot because of poor circulation. I was desperate to find some kind of solution to the constant fan and the software did confirm that the computer was running hot. However, since the vents have been cleared, the temperature has gone back to normal ranges and the built-in fan speeds work just fine.

"It will have just the opposite effect by just blowing/forcing more dust, dirt and lint into the inside of an iMac making it run even hotter."

Who gave you this piece of mis-advice? I suppose someone who doesn't know how to use such a gadget; you invented it in your imagination; you got this from an unnamed user you admire.

I saw a YouTube video on this long ago and has been working for me ever since!

Saves me from going to Apple or an Apple service center once a year to pay for them to suck out all of the dust and dirt from inside me iMac.

I use a regular, common everday Hoover canister vacuum.

You can use either a crevice tool attachment and/or just the plain plastic hose end.

You just can't use anything with brushes on it for fear of an electroststic discharge.

You disconnect eveything. Lay the iMac down, screen side down on something soft.

Slowly Vacuum the top slot, if you can wriggle between the stand, vacuum the round center slot.

Slowly Vacuum all of the ports as dirt, dust and lint can get into the ports.

Slowly Vacuum the CD and SD slots and last but not least, remove the RAM cover and slowly vacuum out all the dust dirt and lint that gets in the bottom speaker vents and RAM slot area.

You'd be very surprised how much dust and lint get into the RAM slot area on the bottom of my 2009 iMac.

Just be slow and light so as not to scratch the finish of the iMac!

I have been doing this once a year for the last 5 years I have owned my 2009 iMac.

Works very, VERY well for me!'

Takes all of 15 minutes or so to do the vacuuming out!

Gets a lot of the loose surface dust particles and other dust build up out of these different areas of my iMac

I don't know how much dust and dirt this gets out from deep inside my iMac, but, at least, I am not pushing any additional dust into the innards of my iMac!

It mostly gets the surface sitting and inside perimeter dust and lint out and away.

It's actually almost time for me to do this, once again, on my iMac.

Ya' KNOW???

Effin try this before you just post and berate me and just accuse me of something on this!

This works and the does NOT force any additional dust, dirt or lint further into the innards of the older iMac models.

Not sure if this would work with the new slimline iMacs, but will work very well for any 2007- 2011 iMac model.

My local Apple reselle/repair center showed me their device to clean out a Mac and it is essentially a large sealed box the they put a Mac into that a has high suction vacuum (the vacuum portion looks like one of those heavy duty wall mounted shop vacs) that suxs from both the top and bottom of the box to suck out most of the dust and dirt from both inside and outside of a Mac.

It's a pretty cool looking device for doing this!

Here is a YouTube video, but not the one of the ones I found five years ago.

A household vacuum has much more power than a battery powered hand held vacuum.

This one doesn't show vacuuming out all of the connection ports and the side CD/ SD slots snd this guy doesn't open up the RAM access plate to vacuum the RAM slot area.

AND he uses a brush attachment

I found the brush attachment does NOT work well AND can cause static discharge.

A no-no with electronics. Forget using ANY vacuum attachment with a brush! Period!

The bare plastic end of a vacuum hose or using the crevice tool works really well for me.

So, here is just a simply example.

Go much slower than he is doing in the video.

https://youtu.be/TwASThJaztQ

I use both a can of air AND a shop vac at the same time to clean my Macs.

Start the Shop Vac, run it around the vents, then do this a second time while using a warm can of air to shoot air into the Mac.

Any loose dust is pulled out. I use a HEPA bag in the Shop Vac, and Filtrete filters with a Microparticle Performance Rating of 1500 or higher in my whole house furnace / air conditioning......