The just-released NVIDIA 195.30 beta display driver now delivers on fixed performance for KDE 4.x when dealing with text that hasn't been anti-aliased, GPU acceleration for many more X RENDER compositing operations, experimental GPU acceleration of the X RENDER CompositeTrapezoids, a VDPAU overlay-based presentation queue, and lastly "nvidia-settings --query all" now really reports all available attributes (something we had been after with NVIDIA to fix). The experimental CompositeTrapezoids acceleration support for the X Render extension can be enabled using "nvidia-settings -a AccelerateTrapezoids=1." While not officially mentioned in the change-log, the NVIDIA 195.30 Linux display driver is carrying the OpenCL libraries for properly supporting the Open Computing Language on the NVIDIA GeForce/Quadro GPUs with this proprietary driver.
We have not yet benchmarked these improvements to the X Render extension with NVIDIA's driver, but just today they have requested a new benchmark be added to the Phoronix Test Suite that is an improved version of Zack Rusin's X Render benchmark, which can already be found in our open-source testing software, and is being enhanced by NVIDIA's Aaron Plattner.
The NVIDIA 195.30 beta display driver Linux download links with other notes can be found at NvNews.net.