Hi I am on Ubuntu 9.04 64bit
I am running Compiz effects
I have a 4870 ATI card with the binary drivers installed.
Previously iPlayer and Youtube full screen performance was very poor. In both Firefox 3.0 and Chromium.
It appears that the problem was the flash (I use the standard ubuntu repository version) I have is not detecting the hardware excleration and is leaving it off.
To fix this a config file is needed to turn off the hardware detection.
basically I put the text OverrideGPUValidation = 1 in a file at /etc/adobe/mms.cfg and re-start the browser.
Such a simple fix.
Here is how to do it in steps
Paste in the textCode:sudo touch /etc/adobe sudo gedit /etc/adobe/mms.cfg
Save the file.Code:OverrideGPUValidation = 1
Open a browser.
Enjoy fast full screen video.
Please post if this works for you : I am so pleased it has worked for me.
If this still doesn't seem smooth try right clicking on the flash object and un-checking the "enable hardware excleration" box