from "iShadowMapResolution=2048" to "iShadowMapResolution=4096". I know there is a performance hit... but effing 20?! Is it something on my end?
Most likely yes. Although I have now upgraded to an i5-2500K, I have had no problems playing with that setting using one old GF 8800 GT (which I am still using for the moment) and an even older AMD FX-60 (2x 2.4 GHz), 3GB DDR RAM and WinXP.
But then, I used "medium" overall quality settings, so maybe I had slack somewhere else.
Another thought: It could also depend on your expectations, When I say I had no problems, I am not saying I did high FPS constantly. It would vary from just below 30 (at the most challenging locations) to 75 (when staring at a corner), but be perfectly playable even with my old CPU.