Hehe it's ok, I have mornings like that too.. sometimes evenings as well.
HTML5 seems to employ more CPU resources but it seems to work much better with my netbook than running a full-page (or fullscreen) Flash item.
The browser you use will certainly make a difference. The major ones (Firefox, Chrome, Safari, Opera, and IE9) run HTML5 quite beautifully.
I'm curious how well HTML5 runs on mobile devices and mobile browsers.