QUOTE
For those wondering, Patch 1.4 contained an unpublished fix for the day-time bug where the day of the week name would not change over when it was supposed to even though the game day was.

Source: http://www.skyrimnexus.com/news/article.php?id=51

Everybody should know that this particular bug was caused by the ini setting, 'PresentInterval = 0' , which is VSync, basically.

Win.

Wait, so we don't need to use vertical synchronization for vertical synchronization? Madness.

Some people don't need vertical synchronisation though. Also, turning it off fixes a a good bit of mouse lag.

It also frees up like 10 FPS.

But this bug was not caused by vsync, contrary to popular belief. Plenty of people playing with vsync on reported the same issue.

One problem that IS vsync-specific is crazy physics in certain places (items flying around when you are in a certain spot).