Executive Producer at DICE, Patrick Bach, has said that the Xbox 360 version of Battlefield 3 is running the game without the high-resolution texture pack (which is found on the second disc) by default, and is the "standard def" version of the game. What the texture pack does, is bring the Xbox 360 version up to the same standards of that found on the PS3 and PC. Bach elaborates:
So what it does is it gives you the same abilities, kind of, as the PC and PS3. You can actually stream information from the hard drive. That's new for Xbox 360, but it's not a new idea for the gaming industry as a whole. No one has really tried to do it properly, so us doing it will create question marks.
Bach has recommended to anyone with the HDD to install the texture pack as it makes a major difference.
It does make a difference, yes, absolutely. The whole engine is based around streaming textures, streaming terrain and a lot of other content. The thing with the 360 is that you need to be able to give consumers a game where you don't have to install it on a hard drive, because there are 360s without a hard drive. So we need to give you the option of installing it, rather than just demanding it. You could call it a 'standard-def' version for the 360 if you don't have a hard-drive.
We're really trying to push the limits of what we can do on the consoles and the PC. Our goal is to see how we can utilise as many of the systems that you actually have in your machine that some people haven't utilised before. Some (developers) just do it like, if it doesn't fit into memory we just make a lesser game. We don't do that. For us, it's about how we can give you the most game ever even though the hardware is over five years old.