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Numbers eats 70% CPU when mouse hovers over document

This happens only on my new MacBook Air 11" and only since I upgraded to Mountain Lion.


Whenever my mouse pointer is over a Numbers document (not the window title, but the actual document), CPU usage by Numbers.app goes to 70% and stays there until I move my mouse somewhere else.


Did anyone else experience this?

Posted on Aug 2, 2012 4:05 PM

Reply
132 replies

Aug 3, 2012 4:01 AM in response to maiksd

maiksd,


I get a small burst of Numbers activity when I move the cursor over a table in Numbers, and another burst when I move the cursor back off the table. Haven't seen it go even as high as 10% on this mid-2010 MBP. So, no problem here. I have about 850 MB of free RAM and about 175 GB of free HD. If I find myself in a situation where the free RAM is about gone, I'll try this again and see what difference that makes.


Jerry

Aug 3, 2012 4:16 PM in response to maiksd

Just as an illustration. This is activity monitor in background sorted by CPU descending, and Numbers.app in the foreground. The mouse pointer sits over Number's big gray window title bar.

User uploaded file


Now just the same, but moved the mouse pointer downwards onto the document content:


User uploaded file


And it's really always 70% on my machine. Never 100% or 50% or anything else. Always between 69% and 71%.

Aug 4, 2012 12:37 AM in response to maiksd

I have 8 GB memory on my computer and CPU usage is still about 70%.


I also tried the following things:


1) Restarted the computer

2) Reinstalled Numbers with the latest version from the App Store

3) Verified Numbers file permissions

4) Checked that I don't have any corrupted fonts on my computer

5) Ran opensnoop to see if Numbers has any weird disk activity during the high CPU usage


Still no luck.

Aug 4, 2012 5:45 AM in response to mttl

mttl wrote:


By the way, I sent some days ago a bug report to Apple concerning this issue by using the Numbers/Provide Numbers Feedback menu. This sends you to a web page where you can choose feedback type "bug report".


I recommend that you do it too if you have not done it yet.

You guys are doing the right thing in reporting this. I'm not trying to convince you of anything one way or the other, just reporting what is going on in my case. On my side, I'll be upgrading to 8GB.


I'll continue to look for clues as to the cause.


Regards,


Jerry


Edit: Please, if you haven't, test with only Numbers and Activity Monitor running.

Aug 5, 2012 1:58 AM in response to maiksd

Jerry,


I tested to run Numbers without having any other applications running. Before that I deleted the following preferences / cache files and let Numbers to re-create them.


~/Library/Caches/com.apple.iWork.Numbers/

~/Library/Preferences/com.apple.iWork.Numbers.plist

~/Library/Preferences/com.apple.iWork.Numbers.LSSharedFileList.plist


I also tried to run it with another user account (admin) in case there is something wrong with my user profile.


In both cases Numbers CPU usage is still high.

Aug 6, 2012 5:31 AM in response to mttl

I've reported this to Apple as well. I have a late 2011 MacBook Pro with Mountain Lion and Numbers 2.2 (516) and see 80-85% CPU usage when the mouse is hovering over any table in Numbers, just like maiksd shows.


Rather than posting a CPU graph, as that's clear now, I thought I'd look at what this does to my machine's temperature. Enjoy this:


User uploaded file


It's obvious that such a commonly used application is causing battery life and heat problems for users. Given that Apple puts a developer armed with a profiler on this, it should be solved soon. It's so easy to reproduce that I'm surprised it wasn't caught before GA. They may may find out that this is not a Numbers problem specifically but something in the OS X display code somewhere. That's not our problem as users, we just call it as we see it.

Numbers eats 70% CPU when mouse hovers over document

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