Necessary to maintain high frame rates
Apparently, Sony isn’t taking any chances with upcoming 3D title releases. The company has issued an official mandate that 3D titles are to be capped at a resolution of 720p, even if the title supports 1080i/1080p in non-3D mode.
From what our sources tell us, the decision by Sony is to make sure that 3D titles are able maintain 60 frames per second in 3D mode. While some rumbling that we are hearing suggests that the decision is to give players a “more cinematic” gaming experience, the reality might have to do more with what the GPU in the PS3 is able to generate (due to the necessary process of having to render two images at a time for each frame).
While some have maintained that the vast majority of users will never really notice the difference between a 720 and a 1080 image, we do know that in order for the PlayStation 3 to be able to produce the 3D effect some sacrifices in raw image detail have been made. Of course, Sony isn’t being specific on what these visual sacrifices actually are; capping the resolution at 720p is apparently the best compromise.