Re: VDPAU and KDE 4.8 compositing = slow
I have the same issues as RealNC and Pie-rate.
Especially RealNC and i have a very similar machine (i5-2500k + Geforce 560 ti) although im running Arch Linux 64-bit. All the system packages are at the latest stable versions, including the geforce driver (295.53).
One more thing i notice is that playing a file with mplayer + vdpau (composition enabled), i get a high cpu load for X.org process according to top. This is particularly visible playing a big, HD video (ex: 8 Gb 1080p 23.9 fps x264 compressed video).
If i do the same above thing but with the Kwin "Suspend desktop effects for fullscreen windows" option enabled, in windowed mode the same applies (high cpu load for X, slow desktop response, frame skipping).
But if then i go fullscreen and let the video play for some seconds, the frame skipping stops. Then if i go quickly into window mode again and look to top, i briefly see that X wasnt using alot of cpu (everything looked to behave normally when the video was playing FS). But of course in window mode the problems come back. So it seems that that option does what its supposed to do (at least with mplayer) and the problem maybe between the driver communication with X and then Kwin composition.
But even the Kwin "Suspend desktop effects for fs windows" is not a option because with that enabled, flash in fullscreen has tearing. And i cant use hardware acceleration with flash because the plugin is always crashing.
And i have to use Xv or GL to watch video files.
Hope you can find a solution for this since this is a problem that exists for a quite few time.