I just installed a fresh install of 14.04.1 tonight after being away from Ubuntu for a while due to failed updates making it unusable. I have it working but then tried to watch a video on YouTube. The sound was fine, but the frame rate was terrible. Closer to seconds per frame instead of frames per second.
For instance, on the first mission in L4D2, it took, after loading, five minutes to get through the part of the scene before you start controlling the character. Five minutes. And it wasn't done by then. I just got sick of it and tried to change the video settings to the lowest settings. That did not help one iota. After another minute, I quit the game, which took another minute or two.
I'm using an EVGA GeForce GTS 450 card, an AMD Phenom(tm) II X4 B55 Processor × 3 (black edition) (sold as two core and I unlocked a third core) with 20gb of ram. I shouldn't be having any trouble, especially not on a windowed mode game at the lowest settings, or on YouTube videos at the lowest resolution, either.
How can I fix this issue? It's almost enough to hunt down a torrent of Win7 just to get the games I want to play running. Not quite, but close.