I tried this with FRAPS running, to monitor framerate.
As far as I can tell, there is no performance increase to be had. The FPS goes above 60, but that's just because it's not capped to my refresh rate anymore.

Did it, and it didn't chance anything for me (560ti SLI)

Didn't make any difference for me, except now I get tearing.. Asus HD6950

That's weird, for me there was a clear and noticeable difference.

Disabling water reflections will obviously give a performance increase while disabling Vsync will only increase your maximum framerate and obviously is prone to tearing, this is a non-solution.

One alternative to this approach of turning off vsync through the ini settings is to force triple buffering.

I compared using the ini tweak suggested, to leaving vsync on and forcing triple buffering via D3DOverrider before starting TESV and honestly I like the second option better.

For me it was like this:

- vsync off - 40 fps but some stutter and small amounts of tearing when turning quickly, etc. Also stuttered in spots
- vsync on, plus triple buffering - 32 fps steady, with smooooth movement, very few stutters if at all.

But you're right, disabling vsync will improve FPS. I just found it a little wild and uncontrolled in comparison. Probably depends on hardware. Thanks for sharing though. I'm sure it's helpful to many.

Man i love this guy!! he's open minded and thorough.

Am I the only one who can't seem to uncap/turn V-Sync off? I've added that iPresentInterval=0 line in the .ini file with no difference. I've forced V-Sync off on CCC for my ATI card and it still refuses to go above 60 anywhere. I'm using 6870x2 though I've disabled Crossfire for the moment. Am I missing something here? I have mouse lag and button response delay at places where the game runs at 60 fps. If I click too fast on my left/right mousebutton, my character won't attack. I don't have response issues in any other game. Neither did I have it in Oblivion.