I try to make videos smooth playing on a Lenovo E325 laptop equipped with AMD E-450 APU. This processor have Ati HD-6320 GPU integrated.

I installed ATI proprietary driver (Catalyst 12.04) as described here. Everything went fine and got no errors. However I can not play smooth HD videos. Almost every second frame has been dropped in VLC with hardware acceleration enabled.

vainfo shows:

libva: VA-API version 0.32.0
Xlib:  extension "XFree86-DRI" missing on display ":0".
libva: va_getDriverName() returns 0
libva: Trying to open /usr/lib/x86_64-linux-gnu/dri/fglrx_drv_video.so
libva: va_openDriver() returns 0
vainfo: VA-API version: 0.32 (libva 1.0.15)
vainfo: Driver version: Splitted-Desktop Systems XvBA backend for VA-API - 0.7.8
vainfo: Supported profile and entrypoints
      VAProfileH264High               : VAEntrypointVLD
      VAProfileVC1Advanced            : VAEntrypointVLD

fglrxinfo says:

display: :0  screen: 0
OpenGL vendor string: Advanced Micro Devices, Inc.
OpenGL renderer string: AMD Radeon HD 6320 Graphics
OpenGL version string: 4.2.11631 Compatibility Profile Context

and fgl_glxgears produces ~250fps.

Why are HD video frames dropped? CPU doesn't goes above 50% during playback.