Fullscreen video lag

Same problem here too. Im trying to watch fullscreen video from different web sites (youtube, svtplay.se, tv4play.se, tv3play etc) but they all lag.

The computer is a Samsung N150 straight out of the box. All I've done is updated all drivers and software (win7). I've tried the tricks mentioned above without luck. Tried it in IE, chrome and firefox with same result. I've tried it in different screen resolutions. Funny thing is that if I set the screen to 800x600 the small (un-fullscreened) screen is almost filling the display and plays well, but when I put it on fullscreen, which practically only makes it a few percent larger, it starts lagging.

I've got an old hp tablet pc with less ram and less process power, but no lagging.

What is going on Adobe?

Fix this!

I forgot to add, I'm using the latest version of Adobe Flash player (10.1) that was released earlier this week.