The rumor isn't that far-fetched since we previously heard that Sony will be using an AMD APU as well as a Southern Islands GPU in its next game console. A patent describing an automated GPU switching process provides further credibility that Sony is aiming for a flexible, power optimized GPU infrastructure for the PS4.
The patent application for "dynamic context switching between architecturally distinct graphics processors" was already filed back in 2009 and published in late 2010, which would indicate that it is not the latest information on Sony's development. The purpose of the GPU switching technology is summed up by the patent application authors as follows:
"It would be desirable to allow the context switching to be hidden from the user and performed automatically in the background. Unfortunately, no solution is presently available that allows for dynamic, real-time context switching between architecturally distinct GPUs. The closest prior art is the Apple MacBook Pro, from Apple Computer of Cupertino, Calif., which contains two architecturally distinct GPUs but does not allow dynamic context switches between them. Another prior art solution is the Scalable Link Interface (SLI) architecture developed by Nvidia Corporation of Santa Clara, Calif. This architecture lets a user run one or more GPUs in parallel, but only for the purpose of increasing performance, not to reduce power consumption. Also, this solution requires the two GPUs to be synchronized when the system is enabled, again requiring some amount of user intervention."
The document does not specify a target product for the technology, but the full automation without user interaction hints to a consumer device and not a notebook computer.
Sony recently filed several patent applications that may hint to the future PS4. Most interestingly, an application entitled "game device" and filed in September of this year reveals a game content screen that is much more focused on community interaction and appears to be much more dynamic that the current screen of the PS3.
