Well, I installed v310.14 beta on Kubuntu 12.04 KDE 4.9.2 from Xorg Edgers PPA. Be careful if you enable this PPA. Read the warnings from PPA site. If you enabled it, just install "nvidia-current" 310.14 and "nvidia-settings". Then again disable the PPA.
GT430 nVidia card.
The video playback when KDE effects are active (OpenGL) have poor performance (1080p). In SMPlayer, using VDPAU is even worse than with Xv. The quality improves when the effects are disabled or using XRender instead OpenGL. Is this problem related to these patches for KDE that you mentioned?
Also in nvidia-settings I can not find the settings for color/brightness/contrast for video (Xvideo). I refer to these configurations for video. These settings for color correction for screen there are.