I think this will cause some controversy.
"RAGE: I took the opportunity and looked at the options menu. There were no graphic options beside resolution, brightness, anti-aliasing and GPU transcoding. Is this a limitation of the test version?
This is a feature of the id Tech 5. The Engine automatically adjusts to your hardware to ensure the best performance and graphics the hardware can provide.
For example: You have a video card with 512MB VRAM, 4GB of normal RAM and a decent processor. Now the id Tech 5 adjusts the quality of the Level of Detail to the available resources. If you have twice the RAM the engine scales dynamically up to it, improves the textures and objects in the far look sharper and more detailed. At the same time the engines tries to keep running at 60 FPS even though this is not also possible dependent on the situation."
http://www.idgames.de/showthread.php/12896-idGames-Exclusive-Interview-with-Tim-Willits