Why does Safari freeze on YouTube HTML5 videos?

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?

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

Solution 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