Tried installing it and it had zero effect on my framerate standing at Dragonsreach overlooking Whiterun. Entirely possible I did something wrong, attempting to determine if that's the case or not.
Or maybe SKSE just doesn't work with my dev build of Windows 8? Tried installing SkyUI to make sure SKSE was working and while SkyUI comes up, it also has a warning talking about not being able to detect the latest SKSE...
So to follow up, Chief sent me a save file.
On full ultra, FXAA on, everything maxed, I got 14-15 fps in his location.
With mod, the same 14-15 fps.
Did the same full ultra, FXAA on, but shadows bumped down one level to "high," AA to 4x.
Pre mod, 24-25 fps. Post mod, steady at 30, which may have to do with vsync holding it there (I notice it pegged to 30 a lot in some areas).
Coming out of breezehome, I used to take a huge hit to 25ish fps for a few seconds before leveling out at 30ish, with mod, drops to mid 30s then levels out at 45 or so.
Definitely seems to have a noticeable improvement on my system. I'm also running skyui and the hd textures mod, for reference.