After searching ages for the reason why Youtube HD Flash videos run fine on my laptop (Even two at the same time!) but not on a friends laptop with mostly identical hardware we found out that it’s depending in the installed architecture. Debian Lenny 32bit has major problems playing flash videos (doesn’t matter whether you get it from backports or adobe) but the 64bit version has none of them. It seems like the 64bit version of the flash player has insane benefits from 64bit – I really wonder why! I still have the tearing problem most Intel GPUs have, but at least it runs fluent 😀 I am pretty sure Squeeze and Ubuntu are affected as well, though we only tried Squeeze 64bit and it was fine – as expected.