As reported by the French site HardMac, MovieGate developer Christophe Ducommun found his app jumped from 104 frames per second encoding under Leopard to 150 fps performance on the same hardware under Snow Leopard after implementing support for the new features.
Grand Central Dispatch helps developers efficiently maximize multiple processors available on the system, and OpenCL enables applications to make use of the latent power within available video card GPUs.
In addition to an overall performance boost in output, Ducommun also reported CPU utilization for MPEG-2 encoding under the ffmpeg open source library leap from 100% to 130% on his quad core Mac Pro, indicating a significant improvement in tapping its multicore potential.
At the same time, decoding operations dropped CPU utilization from 165% to 70% under Snow Leopard because a significant amount of the work could be delegated to the machine's GPU.
The observations illustrate how Snow Leopard's Grand Central Dispatch and OpenCL combine to improve performance both in raw computing power and in increased use of otherwise idle hardware.
In particular, it indicates the potential for GPU delegation to speed things up while reducing the load on the CPU for some operations, particular video playback. The battery life of mobile devices stand to benefit from such optimizations.