I'll click the fullscreen button, and then Opera just freezes for an entire 15 seconds befofre it goes fullscreen. I've tested going fullscreen on other browsers such as Chrome, Firefox and IE, and it does not freeze for any of those browsers.
I think it may have something to do with a certain Java plugin? Java will simply refuse to work inside the browser, meaning anything that requires Java will not load.
Regarding the fullscreen issue, my CPU is not the problem. I am running an e8500 with 4gb DDR3 RAM, 3450 graphics.