Grand Central Dispatch and Open CL Bring Significant Performance Improvements for Optimized Applications

Hardmac reports on a performance comparison between Mac OS X Leopard and Mac OS X Snow Leopard from Christophe Ducommun, developer of MovieGate, a video encoding and DVD creation software package. Ducommun, who is optimizing his application to take advantage of the Grand Central Dispatch and Open CL features of Snow Leopard, has found remarkable performance improvements for his software on the operating system when running on a Mac Pro.

Christophe Ducommun who keeps optimizing Snow Leopard for his application MovieGate just sent us results to illustrate how Snow Leopard can improve performance when one can make use of Grand Central and Open CL. Tests below have been performed with a Mac Pro 2007 (Quad Core 2.66 GHz with a GeForce 8800 GT).

The results include an approximately 50% increase in video encoding speed when compared to Leopard, while also reducing the CPU load during video decoding by passing some of the work to the graphics processing unit.

Snow Leopard
150 frame/s for encoding in MPEG-2
70% CPU load for decoding
130% CPU load for MPEG-2 encoding (ffmpeg)

104 frame/s for encoding in MPEG-2
165% CPU load for decoding
100% CPU load for MPEG-2 encoding (ffmpeg)

While Ducommun's experience is relatively rare at this point due to the inability for the vast majority of applications to make such comprehensive use of Grand Central Dispatch and Open CL at this time, it highlights the potential performance gains these core technologies can bring to Mac OS X as developers begin to take advantage of them.