Why is my late 2013 iMac so slow? For the last three months I have been more or less enjoying my new late 2013 21" iMac. I already have an early 2011 MBP, which is pretty maxed out with a 512GB SSD and 8 GB of RAM, and still feels very, very fast.

The iMac has 8 GB RAM as well, but "only" the Intel Iris GPU and a 1TB SATA HDD. Both machines are running OS X 10.9.4. 

Starting up a few apps, like Mail, Safari and maybe iPhoto, takes ages. Sometimes up to 20 or 30 seconds. Whereas the MBP takes only a handful seconds. It's clear to me that the SSD gives a great performance advantage. But is it really that much...?

I also noticed in the systems report that the Iris uses sometimes up to 1.5 GB of RAM. This seems like a lot. I imagine that this could also hurt performance.

I also get a lot messages like these in the system log:

24.08.14 19:57:32,827 WindowServer[539]: disable_update_timeout: UI updates were forcibly disabled by application "iPhoto" for over 1.00 seconds. Server has re-enabled them.


These happen if I switch from one iPhoto event to another, or switch to my iCloud albums. On the MBP this happens instantly, without delay.

Update: Here are some screenshots of the activity monitor and Console logging:
i've seen this on some of my machines... it is fixable (though ican't remember the details for my situation). but it will stay very slow until you clean out those ui/windowserver errors.

firstly:
have you added any screensavers?
have you safe booted to clean out caches and check HD?

http://www.macworld.com/article/1163410/bugs_and_fixes_when_os_x_lion_slows_to_a_crawl.html