I found BIG differences between video players.
1680 x 1050 monitor. Sorry, I don't have 1080p HDTV yet.
I installed ATI 11.2 driver, & Flash 10.2
Use the following NVIDIA 1080P test videohttp://www.youtube.com/watch?v=XITHbsUUlYI
Using Chrome watching 1080P video on Youtube use ~70% CPU, always buffering.
after downloading the same mp4 video (using Jdownloader)
VLC 1.17 ~50% CPU, not usable at all. Will stop completely anywhere in the video for several seconds.
KMP 3.0 ~70-90% CPU, good, but not smooth enough.
Windows Media Player ~22-35%, smoothest, no stutter, no skipping.
Either AMD/ATI need to improve their driver or VLC/KMP, etc need to step up & improve the support of this platform.