Videoram is for framebuffer and shaders friend, not for gamelogic, therefore
the VRAM does not matter.
Another thing: the PS3 sdk uses opengl while Xbox 360 uses directx, making it much easier to port to Xbox then. The PS3 graphics renderer of the engine has to be rewritten for a big part, while on Xbox it will take considerably (spelling?) less time to port.
On the other hand, a PS3 always has a harddrive to stream data off, while xbox360 does not always have a harddrive (ie. arcade edition), so the developers have to fit the whole game in 512 ram, without the assumption
to be able to stream from harddrive.
It will provide serious development challenges on either console, that's for sure. If they can pull it off on any of the 2 consoles without serious downscaling of maximum AI/objects or the size of the map, i will be nothing
less than surprised! :)
I hope they do, cuz i don't care about console vs pc or PS3 vs xbox flamewars.
BTW, i own a pc, not a console :)