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On Snow Leopard (10.6), the screen recorder on QuickTime Player worked just fine. However, since I have upgraded to Mountain Lion (10.8) QuickTime screen recorder has been making my 2010 MacBook Air extremely slow/laggy while recording the screen but once I stop recording my computer is no longer slow/laggy.

Is there a way to fix this annoying problem? My computer is pratically unusable while recording so I can't use QuickTime to record the screen until it is fixed.

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Could you check if it indeed is Skype slowing down your computer with Activity Monitor? – pasawaya Aug 1 '12 at 6:42
@qegal I didn't say anything about Skype, and I don't have it running. Do you think it could be a bug with QuickTime? – Nathan Aug 1 '12 at 7:11
Sorry. I typed Skype for some reason but meant QuickTime. I haven't heard anything about QuickTime making computers slow. – pasawaya Aug 1 '12 at 7:13
@qegal While recording, at some points it takes up over 90% of the CPU and usually stays between 30% and 70%. I don't see why it's doing that. – Nathan Aug 1 '12 at 7:27
@qegal Here's a screen shot of Activity Monitor while recording on QuickTime:… – Nathan Aug 15 '12 at 5:24
up vote 4 down vote accepted

Not exactly a solution, but some observations that might provide a clue:

  • Issue also seen on my Mac mini (Mid 2011 - 2.7GHz Intel Core i7 + 8 GB DDR3) after upgrading from Lion to Mountain Lion
  • QuickTime no longer saves the recording to ~/Movies/Screen, but instead saves it to some temp location and when done recording, you need to save/export it.
  • Downgrading quality to medium quality didn't help

[Update 11/17]

Even my new Macbook Pro Retina 15" has this issue.

I happened upon a tutorial that showed someone using VLC to screen capture on a Mac and decided to give it a try. It turns out that functionality was removed from VLC on Lion and Mountain Lion and the reason was provided in this this thread: Mac OS Lion, VLC screen capture does not work:

Apple completely removed the API to capture the screen and replaced it with something totally different. Until anyone steps up and implements the new one, this feature is not available to Lion users. It remains accessible to Snow Leopard and Leopard users of course.

I'm not sure if this is also what's causing QuickTime on Lion+ to be super slow.

I did find an alternative which is working out really well for me: Voila

Available on the App store for $10 and records w/o performance issues. I was skeptical at first, so I downloaded its trial, and was extremely happy with the performance. $10 is definitely more than free, but depending on how often you need to record your screen, this is well worth the money in my opinion.

It supports both JPEG and H.264 encoding, but only records up to 25fps. For audio, it allows you to select which input and even allows you to use the computer audio (something QuickTime didn't allow and you had to use a separate utility like Soundflower).

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Yeah, I set it to medium as well but it didn't help. Quicktime's screen recorder is a piece of junk in its current state. Apple needs to fix it. – Nathan Aug 15 '12 at 5:23

I recommend changing the setting "Automatic Graphics switching" in your system preferences to off. It helped me.

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Could you explain this setting? MacBook Air have one graphics card so it's not clear what switch is possible unless you are referring to some hidden preference or third party software perhaps. – bmike Aug 29 '12 at 16:07

I believe that Apple has upgraded Quicktime's API's for high definition beyond 1080p etc. There is nothing wrong with quicktime per se. It's just laggy with older macs. Maybe faster SSD, more Ram might help?

Or cheapest fix is install the correct OS that came with your mac. Downgrade one OS level greatly increases overall speed of system and brings back Quicktime quickness.

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