It's ATI Stream versus Nvidia's CUDA in this GPGPU-on-IGP shootout. We benchmarked the Cyberlink Espresso video converter, which is conveniently optimized to take advantage of both CUDA and ATI Stream and seems to be an ideal test.
Maybe not so ideal after all, as these results look somewhat strange.
We had a few odd occurrences of note during testing. First of all, when Espresso was run on the Nvidia 9300 chipset, the program gave us the option to turn hardware acceleration on or off, presumably to enable/disable the CUDA optimizations. The strange thing is that when optimizations were enabled, the video encoding took longer, which is the opposite of what we expected. We asked Nvidia about this phenomenon, and they claim that their testing shows even a 3 GHz Core 2 Duo E6850 should demonstrate a performance increase with CUDA enhancements enabled.
Nvidia also pointed out that these results are misleading unless the resulting encoded video is bit-for-bit identical, and they claim that their encoding is of a higher quality than the video resulting from the ATI Stream optimizations. They were also concerned that the version of Cyberlink Espresso AMD had provided was not a publically available build. We were actually working with both companies (and Cyberlink) on an image quality comparison, even before 785G showed up, so you can expect more detailed coverage there as soon as that project comes together.