Over the weekend http://www.joystiq.com/2010/07/16/sony-limiting-use-of-1080p-3d-in-ps3-games/ revealed that Sony is limiting use of 1080p 3D in PS3 games while opting for 720p, and today both PC World (linked above) and http://www.eurogamer.net/articles/digitalfoundry-720p-3d explain why Sony mandates 720p for PS3 3D while admitting the PlayStation 3 can do 3D 1080p.
Sony's Simon Benson
confirmed that the PS3 can do 3D gaming in 1080p, but developers are generally encouraged to keep PS3 3D games at 720p due to frame rates and related issues that may arise with 1080p in PlayStation 3 3D gaming.
To quote: "3D exacerbates the issue, requiring the system process two discrete interlaced images--one for each eye--to fake depth perception.
In an undated tech presentation by a Sony engineer, the engineer admits "rendering two images from the same hardware may require compromises or limit the possibilities," citing performance ("the scene must be rendered twice"), VRAM usage ("the frame buffer may be larger in some cases"), and resolution limits ("more pixels may be processed") as mitigating factors in the list of technical considerations."
According to Eurogamer, to quote: "Tt's simply the case that the new stereo 3D support built into the HDMI 1.4 spec is specifically designed for Blu-Ray movie playback at a standard 24 frames per second, making the full HD mode a poor fit for gaming.
In a world where games are created to run either at 30 or 60 frames per second, dropping down to 24FPS means a jerkier image and a more muted response from the controls."
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