Graphics options.

[Mhaeric]

The Benchmark (maybe they've changed it) prior to the live release of the game had at least 3x as many options that are available in the graphics option menu in game.

You could disable god rays for example, which isn't an option in the live game.

There were more options for screen resolution (such as 1280x600 - widescreen border)

I have both versions of 2.0's benchmarks installed on my computer, with no changes to their files for months and neither of them has an option to 'disable god rays.' Also, every setting available in the benchmark is available in the game, and vice versa. Are you sure you're using a 2.0 benchmark?