khh is correct.
Lowering Shadow Distance to 0 meters makes the game look really horrible. Actually we would like to change that to be a minimum of 5 meters.
That said, I'm sure you understand that we don't want to default to 0m for Shadow Distance.
Currently, the game is defaulted to Medium quality, which in turn places the Shadow Distance setting on 8 meters. Changing Visual Quality in-game you'll see that the Shadow Distance value as well as DoF is changed for certain levels.
But really, the shadows shouldn't have such an impact on how the game performs on your computer unless you have a pretty old GPU, which I guess you don't have since you are mentioning this as a problem(?).
"Try lowering settings" is really a general term here. Different people have vastly different systems. For some, their CPU might be the bottleneck. For others, maybe the GPU or available system memory is the culprit. All of which are impacted by different settings (i.e. Post Processing effects are generally hogging the GPU, Texture/Visual Quality is more of a RAM thing, etc.). So, it would mean a lot of work to put together a Q/A for every different scenario.
We are trying to update the FAQ when new issues arrive, or issues that will have to be explained in a more specific way.
Hmm, we could actually update with something along the lines of what I just wrote above. That would be a bit more specific. Hey, I guess you just made me do it after all..