Outlook 2013 periodically has high CPU usage and really slows down everything.  Fortunately, restarting it brings everything to normal, so this issue is not a big deal but only a minor nuisance.

It would be nice to completely prevent it.  Any tip is greatly appreciated.

As shown in the screen capture, all add-ins have been disabled

That can be Antivirus or Indexing process

You can take look on Task Manager

Task Manager shows OL uses 25 - 30% of CPU on an Intel quad-core machine.  I have disabled Windows 8 indexing due to another issue.  Restarting OL restores normality. I have not disabled anti-virus yet, but I will try it next time when this occurs.

I disabled antivirus when this happened again, but it did not make any difference.

Restarting OL is still the only remedy that I know, but it is not a big deal.  The nuisance is that the high CPU usage is not felt until it really slows down everything.

Then try to start Windows in clean boot to check whether the issue is caused by some third party services.

The problem is that it does not happen immediately after starting Windows. It may not happen for an entire day.  What I can do next time is trying to shut down other programs and services one by one when that happens again. 

I've had the same issue.  Outlook 2013 choking the processor and hanging for 2-5 seconds at a time.  Most often this has been when replying to an email (new emails creation, not so much).  So far, the best performance has been when I have the RIBBON set to SHOW TABS ONLY, hiding the rest of the COMMAND RIBBON structure.  Try this out and see if it helps..

Thanks, David.

Actually, I have not had this problem for a while.  I am wondering if one of the Office updates has taken care of it.  I will try your method should it happen again.

I have the same problem and it's driving me crazy.   A seemingly random amount of time after starting my laptop, Outlook uses 13% plus CPU continuously regardless of whether I'm using it or it is minimised.

On my HP Envy 8 core i7 laptop, this causes the fan to run up at high speed all day.  The only way to stop it is to close Outlook.  The problem doesn't return as soon as Irestart Outlook but it always comes back after a while. 

I have the same issue as Turhan.  I have Outlook 365 home premium (2013) on Windows 8.1, new HP Envy quad core i7 (4th gen).

I have had to resort to accessing my email via a web browser.  Outlook CONSTANTLY lags, sometimes even 30+ seconds - 1 minute or more.  I have to use task manager to close it.  Then it will lag in the background processes and I have to go into task manager again to fully close it.

I've performed quick repair, full repair, spent 3+ hours with MS tech support, disable anti-virus & firewall, reduced the size of my data file by 1/2, and more.  I've got the latest windows, Office, and other software updates.  NOTHING IS WORKING!

The rest of my computer is working flawlessly, no issues.  Even when Outlook is having issues, I can use the rest of my computer w/o any problems.

any suggestions?

I get something very similar when I close Outlook.  The CPU goes to 100% and when I look in task manager it's OUTLOOK.EXE using 95%.  Ironic that I have closed the program.  I try not to run Outlook as the perfomance is generally problematic as noted in this forum thread.  OWA gives me much better results. 

• Edited by MS...CF Thursday, October 09, 2014 1:54 PM spelling/grammar

Absolutely the same Problem here, in my case this lasts now for several hours the whole Computer is slowing down...

This problem is still not solved.

In my case Outlook is eating 50% CPU time when I open certain email folders e.g. Inbox and it is returning to 3% CPU when I switch to e.g. the concept folders. It started just a few weeks ago after a regular microsoft patch round. So I wonder if it has something to do with an update for Outlook.

The strange thing is that if I hide the ribbon (see this post DavidIanWarren) there is no CPU problem.

How can the ribbon structure eat 50% CPU time?