I'm not trying to be an ass here, but I don't find that guide useful. Actually I couldn't find a single piece of useful information and the bit I found is not something that I hadn't read in either of the following two guides which I would much sooner recommend:
Official tweakguides.com Crysis tweak guide
Mad Boris' tweakguide on incrysis.com
And btw I notice a pretty good difference between medium and high shaders. For me I get what I pay for in FPS.
Anyways I guess that GS guide can be alright if you've not played crysis yet or have absolutely no idea where you stand performancewise with some specific system specifications. Tweaguides.com also had those low, medium, high, very high comparison shots of each setting, but it's always nice to have more I guess