Sudden choppy lag spikes out of nowhere.

@28s87cm7gcj2  Your computer should be able to handle ultra settings, and even having to resort to laptop mode for smooth play would be a problem.  The reason I asked about a new save is to see whether this is an overall game issue or more specific, for example just this save or the lot.  So please do test a new save just to see what happens.

MCCC shouldn't cause this kind of lag, at least not when you're simply moving the camera around with the game paused.  But please test with no mods at all, to be thorough.

On a separate note, did you recently reinstall Windows?  I ask because your dxdiag lists no errors at all, which is very unusual.  If this isn't a fresh install, that suggests that Windows can't read the error report data, which in turn suggests a system issue that should be addressed.