I'm in YouTube HTML5 trial, and the experience is terrible with Safari.
Every video is lagging severely, and the browser gets unresponsive constantly.

I have zero problems with the Flash version, and Chrome handles HTML5 YouTube just fine.

Activity Monitor says QTKitServer - Safari Web Content grabs more than 100% CPU.
Can I fix this?

image showing 100% cpu usage

I have 17-inch Mid 2010 MacBook Pro running Mac OS X Lion 10.7.2 with 8 GB of RAM.

  • 1
    You should report your experiences via the "feedback" link on that YouTube HTML5 web page.
    – bneely
    Jan 22, 2012 at 0:24
  • 2
    A bit more info on your computer could be useful too. OS version, model, year, etc.
    – kevin9794
    Jan 22, 2012 at 1:23
  • @bneely: thanks. I just reported it.
    – Dan
    Jan 22, 2012 at 3:02

1 Answer 1


I had a similar problem with my Safari. I went into /Library/Internet Plug-Ins and removed the two piece of Flash cruft (regretfully I'm at work, so I don't the exact file names.) After a reboot, Safari worked much better, as did Chrome. Not sure why Chrome improved, but it improved most of all.

Incidentally, I thought I was on a Flash free system previously, so I'm not sure how those bits got there. If I need Flash, I just go to Develop -> Open Page With -> Chrome (you need to enable the Developer Menu, under Advanced in Preferences.)

Hope this help


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