WindowServer High CPU

second display is a likely culprit

I had the same issue. CPU starting at 20% and steadily increasing up to 80-90% with peeks of 120%. I was thinking of uninstalling Yosemite (and even Mavericks!) and revert back to Mountain Lion, which seemed to be way more responsive. That is, until I unplugged my external display. Now WindowServer seems to be mostly between 6% and 10% and my Early 2009 iMac 8GB RAM with Yosemite works like a charm. But I cannot use my external display.

 

Actually you may be right.

I was using the A1305 Mini DisplayPort to DVI Adapter:

http://www.amazon.com/Apple-DisplayPort-converter-cable-adapter/dp/B0056XME46/ref=sr_1_1?s=electronics&ie=UTF8&qid=1413812748&sr=1-1&keywords=a1305

I am now trying with the A1307 Mini DisplayPort to VGA adapter:

http://www.amazon.com/Apple-Mini-DisplayPort-Adapter-MB572Z/dp/B009K916ZK/ref=sr_1_1?s=electronics&ie=UTF8&qid=1413812843&sr=1-1&keywords=a1307

(my external display supports both)

So far it seems that VGA is causing less problems compare to DVI. I hope it stays like that!

 

Same issue on my macbook pro, that's the major difference i'm noticing between mavericks and yosemite

 

External video solutions like yours are dependent upon third-party drivers to work. Hopefully yours will be updated by the vendor. You should go to Accell's website and see what they say.

 

I'm having the same problem with high CPU usage when my second monitor is attached. I'm using Apple's official display port to DVI adapter.

 

I'm on fully spec'd late 2103 iMac, with a secondary monitor and had absolutely horrible performance when updating to Yosemite, nearly everything was very very slow. I has no choice but to go back to Mavericks.

The odd thing for me was I checked Activity Monitor and nothing was being maxed out.

Well I hope that this was the cause of the problem and Apple sorts it out. Otherwise no Yosemite here.

 

Same issue here on both a 2009 MBP and 2013 rMBP. Clean Yosemite installs. The minute I unplug the external monitor, the choppiness and high WindowServer CPU usage disappears. Looking at performances after several hours of usage, windowserver has used way more CPU Time than any other program or process. There's definitely an issue there.

 

Oh oh. We have a time traveller over here!

 

External display's high refresh rate may be the problem?

I have good news.

Premise: my external display can work at 60Hz or 75Hz. With Yosemite Beta, I had a problem with the screen savers. I solved that problem by increasing the display's refresh rate, from 60Hz to 75Hz. Then I forgot about that - didn't think it would cause any issues. Now my computer is running Yosemite, no Beta.

And this is the good news: Decreasing the external display's refresh rate to 60 Hz seems to solve the problem (I'm using HDMI connection again now, so no issue there!). I seem to have no problem with the screen savers, and WindowServer CPU usage and system performance seem to be back to normal.

***UPDATE EDIT*** After some time the problem is back. Even with 60 Hz. The only working solution so far is to physically unplug the external display

 

Same problem here on a 2013 Mac Pro.

I noticed that disabling Little Snitch dropped Window Server usage quite a bit, but the UI lag is still there.

 

I have been having a similar recent problem with WindowServer high CPU, causing sluggish response of my 2011 Mac Mini when I'm using the desktop to move some files around. Running dual displays here.

It seems to be an issue with window transparency first noticed during the beta test program, according to some other discussions. I checkmarked the "Reduce transparency" box in System Preferences / Accessibility and it makes the problem go away. Hopefully Apple will fix it soon.

http://www.macissues.com/2014/10/20/prevent-the-windowserver-process-from-dragging-yosemite-down/

***UPDATE EDIT*** After a half hour the problem is back. Time for a reboot.

 

I don't know about the CPU usage but after my system idles for 5 minutes or so, I go to do something and everything but my mouse cursor is frozen. After about 20 seconds the UI starts responding again. The culprit is definitely WindowServer as my console log is flooded with WindowServer messages. At first I thought it was Firefox due to the highlighted message in the log but that was quickly ruled out.

Kind of sucks when I'm watching a video and the screen just freezes. Really makes me want to go back to Mavericks despite how nice Yosemite is.

 

I'm having the exact same issue of the whole system hanging for 5 minutes including the clock stopping.. I also have high cpu for window server .. the one thing that is really baffling is that this is happening on our 3 Mac Pro's at exactly the same time!

 

Just to add another problem:

I use a second monitor as well and yesterday my MBA 2012 was starting to crawl. Activity monitor did not show a lot cpu usage.

But WindowServer had been using 1,8 GB memory - climbing every second. Watched until it hit 2 GB after a couple of minutes - fans spinning loudly.

Was working in preview at that time.

Did a restart. After that it was back to 55 MB memory. BTW: I have transparency turned off.

 

Related thread

There's a related thread here, with a possible solution.

https://discussions.apple.com/thread/6604961?

That may help.