Using Ubuntu 12.04 with Gnome 3.4.2. When I load video files (avi, mkv, mp4), they play smoothly in windowed mode, but when in full screen, they mildly (but noticeably) stutter. I've tried various players (from VLC to SMplayer2), with many different output drivers and it's always the same.

Also, my video card is AMD Radeon HD 6450, and I've had no luck with the proprietary FGLRX drivers. Every time I install them, my system becomes very sluggish (window dragging animations become choppy etc.).

Thanks in advance, guys.