Thank you for your kindness.
I have a 2009 27" iMac running the latest OS as of Aug 2016.
Problem: It takes a half an hour to move the mouse. Maybe a little exaggeration. But unusably slow.
It seems, in retrospect, to have gotten slow slowly but faster getting slower lately... so now it takes a half an hour to move the mouse.
How can I further diagnose the problem and investigate a solution?
Again, Thanks!
iMac, Mac OS X (10.7.5), QP816017ZCT
Hi commddot!
Looks like you're running into an issue where the iMac is running slower over time and now is to the point that it's hard to do anything on it because of how long it takes to move around the mouse. I can only imagine how that would interfere with being able to use it for normal tasks so we certainly need to take a look into it and see what's going on with it.
One of the first things to check would be to see if there are any Login Items that might be causing the issue. To do this, click on the in the top left and then on System Preferences. From there click on Users & Groups and then on Login Items. If you have things listed there, click on each one and then click on the minus symbol under the box there so that nothing is listed. Then restart the iMac and test it out to see if it's any better.
Also, take a look at the Activity Monitor to see if there are any runaway applications or processes that would cause it to run slower. If there are any that are using a high amount, then go ahead and stop the processes. This article here shows how to use Activity Monitor: Use Activity Monitor on your Mac
If it's still running slow, then we'd need to test it in a new user account, and also in safe mode. That way we can isolate more where the issue actually is. Check out these articles for steps on how to do that:
OS X El Capitan: Start up in safe mode
How to test an issue in another user account on your Mac
Enjoy your day!
Your "slowly then faster getting slower" is curious. Usually, there is some known event preceding a noticeable slowdown - cause and effect - like upgrading from earlier OS X to El Capitan
Since you don't tell us any details of your iMac's RAM or storage, I am guessing that your installed RAM may be the issue - as El Cap is more "hungry" for RAM than earlier OS X versions.
So we can get a snapshot of what is going on... while your Mac is experiencing the slowdown, run http://etrecheck.com/#download and post the report here. The first part of the report is all the technical details about your Mac. There are NO personal details included.
EtreCheck was written and is maintained by a venerable fellow member here etresoft, just for the purpose of helping us here diagnose problems such as yours. It does nothing more than look at what is going on and create a report in a easily readable format. It does NOT run in the background after you Quit.
The Safe Mode startup seemed to regain a lot of the speed that was once lost.
There are probably other things that i can do to throw off dead weight and I would be curious as to what those things might be.
"Safe Mode" startup AND THEN starting up normally again does a lot of stuff in the deep dark recesses of the system.
I will keep my fingers crossed for your continued joy.
Post the EtreCheck report anyway. It will show the things - the dead weight that speak of - that we could recommend you get rid of.
Slow running the latest OS on a 2009 iMac
