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I recently upgraded my mid-2011 15" MacBook Pro to OSX 10.9 Mavericks. Since then, my computer's RAM usage spikes to the point of making my computer unusable. Specifically, anywhere between a minute and 2 hours after booting up, the process kernel_task will use between 4 and 5 GB of RAM (I have 8 GB installed) and mds and mds_store will use around 2 GB between them. At that point all of my apps become unresponsive.

If I don't restart my computer within about five minutes of this happening, OSX will ask me to quit all of my apps. If I don't do that the computer becomes totally unresponsive (even to restart requests) and I have to perform a hard shutdown. If I do, the same thing happens but it takes a couple minutes longer. I talked to an Apple representative and he said to flash my PRAM and reset the SMC, which I did, but nothing happened.

Aside from that he said to send my device in, which I can't do at the moment. Any idea what's going on?

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Usually with new-released software, they will find lots of issues like these when people start actually using it. I would suggest you revert to 10.8 and wait a bit before installing the most recent thing, let them work out the bugs, then jump on board. If you don't suffer any issues on 10.8 - you know it's the new OS. Not ideal, but a thing you could do to make it usable. Hopefully, you made a backup (timemachine or otherwise) of the old system? –  nerdwaller Nov 4 '13 at 12:57
I'll try that. I made a data backup but not a system backup. Is there a way to revert other than to wipe the drive, install 10.8, and put my data back? –  Julien Clancy Nov 4 '13 at 13:00
Not to my knowledge, Apple usually tries to keep people on the "latest". Usually, fresh installs are the way to go - just a pain in the butt. –  nerdwaller Nov 4 '13 at 13:01

4 Answers 4

So I found the same thing with my iMac - Mavericks seemed to be chewing through a lot more RAM than Lion or Mountain Lion.

I found a solution though that doesn't require a reboot: http://osxdaily.com/2013/11/14/use-purge-command-os-x-mavericks/

simply run "sudo purge" (it'll ask you for your password) and it purges the unused memory the OS is hanging onto.

I freed up over 5GB this way without any hitches - although the system appears to hang for a moment or two while it's doing this purge.

I hope this helps!


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I found a similar solution, which is to force quit mds. This makes kernel_task let go of its memory too, for some reason. But it's good to have a more legitimate solution, thanks! –  Julien Clancy Nov 19 '13 at 16:00
Purge doesn’t necessarily do what you think it does. The man page on Mavericks says that it purges the disk cache. In general, purging caches will make things slower, not faster, because things will have to be regenerated and cached. –  Zev Eisenberg Feb 17 at 21:51
best is to force quit (kill) mds here. mds is the metadata server or oversimplified: it's Spotlight. It might be, that the system has to rebuild the whole metadata database after the upgrade and for that it needs to go through every file on the computer. The more files the longer this process will take... so i'd go ahead and kill the processes and let it do it's work overnight. –  Wolfie Feb 17 at 23:30
I have a brand new MBP (10.9.4) with 16GB and kernel_task is using over 8GB. Killing mds didn't help. Is there any other way short of a restart? –  Ze'ev Aug 4 at 21:47

I experienced kernel_task ballooning up to 20GB of RAM and saturating (and not releasing) all available RAM, which essentially froze all of my running apps. Through trial and error I found that it was a runaway R process, as after I quit the R application, the kernel_task went back down to a reasonable 1GB (the R.app did not require more than 1GB of memory at that time).

So the specific fix for my scenario was to restart the R.app application. You might try quitting all running apps one-by-one to systematically figure out which one might be interacting with kernal_task and causing the issue.

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I posted this question in the Apple support forums here and ran some diagnostics at their suggestion. Since running those, I've discovered a host of new problems with my system that were not present before installing Mavericks. Not the least among them, many of my Python packages no longer work (such as flask and pandas), and easy_install and pip are now broken. I was recommended to do a clean install (and consider downgrading in the process), which I will do as soon as is convenient.

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I have an old but great iMac, from 2008 with a max capacity of 4 Gb RAM. Following the Mac recommendations, I made a reinstallation since "cero" of Mavericks, but the performance was still very bad, and the consumption of memory was terrible.

Additionally, under the promise of "making the Mac faster", I had installed Mac Keeper, that by the way was consuming a lot of memory for the antivirus plus the resources of the app turned on.

MY solution: Uninstall Mac Keeper. Immediately I recovered 1.5 Gg of RAM, and after a restart of the computer, it was saving 2.0 Gb of RAM.

Because of the model of my iMac, I still need to resolve the kernel_task excessive consumption. My belief is that I made a great mistake installing Mavericks.

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