Recently I've been trying to get rid of Flash completely - for the most part this is no problem, with the one exception of YouTube. Other people have reported that opting into the HTML5 trial increased playback performance significantly when compared to flash, especially on slower hardware. When HTML5 is enabled I am having a complete slideshow - it's not even really possible to scroll down the page. I'm pretty confused seeming as I'm running a 1.67GHz PB G4 with 2GB. Browser is Aurora (WebM + H.264 supported). After some further reading, it tries to default to WebM on Firefox, which has terrible performance on PPC. After a bit of searching I discovered you can switch to H.264 by going about:config and disabling WebM from in there. H.264 appears to perform even worse though, which is unfortunate. Any clues?