Nathan Lawrence from Atomic Mag chatted with Patrick Bach, executive producer of DICE about battlefield 3. There is an article in the June mag, I don't know if I can post the article here, most of it is already known info except for the lighting and hardware requirements.
Quoted from the article (with some slight editing for ease of typing)
The demo at E3 was run on a computer with standard high end components and a single NIVDIA 580, the minimum requirements for running bf3 are equivelent to the output from the consoles, not CPU vs CPU, but matching output. Patrick went on to say that the computer that will run bf3 on full settings has yet to be built.
One of the most impressive features was the real-time lighting. For the PC we have a dynamic radiosity system that actually bounces light around in real time. The feeling of being indoors will differ quite a lot from outdoors. Also having everything have occlusion; so characters moving up close to walls create a shadow - even if its not a drop shadow - it just occludes light from the surrounding area. And that creates a very physical contact with the world. The physical impact that you make when you run around the environment will actually be enhanced by the lighting. Having nighttime with, y'know, hundreds of point lights instead of a couple. So we can do many things with light that we have never done before. We asked how the real-time lighting would be impacted by the new levels of destructibility in bf3. Patrick responded enthusiastically with this, "Make a hole in a wall and light will then bounce from that new hole into the environment. Again, we're trying to not focus on it as a feature. We see it as a natural part of the physical world you're in. So it should just feel natural to blow a hole in the wall and everything just adapts to that situation and it looks stunning. That's the goal"
So start saving and sweet talking if you are chasing the eye candy...........