So I've been slowly going through the STEP guide and testing performance as I go. I noticed that with 'fShadowDistance=8000' I can pretty much go anywhere outdoors and get rock solid 60FPS no matter what's going on on-screen. However, when walking into a city such as Markarth the FPS drops drastically to 30-40FPS~. I did some testing and determined that the fShadowDistance tweak is the real killer. If I set it down to 2000 instead of 8000 my FPS increase dramatically to 55~ FPS. Now, Markarth is probably the most demanding city I think. Whiterun doesn't run bad at the 8000 value, but my goal in testing this is to get the game stable and playable when it is at its worst.
So this brings up my original question, is there a way I can run two different ShadowDistance settings simaltaneously? Could a mod theoritcally exist which lowers ShadowDistance in demanding cities, but goes back to its original value once you leave said city? That's the only work around I can think of that would solve this problem. If anyone has any ideas on what I can do to get this performance back in cities such as Markarth I would be all ears though!
Note: I tested this performance issue in both vanilla Skyrim and partially modded STEP Skyrim. Performance is terrible in both and adjusting ShadowDistance is the single determining factor in FPS.