Stutter and inconsistent framerates when looking at sun with VSync enabled
When looking at the sun with VSync enabled, the reported framerate will increase from 60 fps to 63-65 fps (despite VSync being enabled), while the actual viewed framerate decreases to 10-20 fps. This happens regardless of whether the VSync used is the one set in the OpenMW settings menu or in NVidia Control Panel. This might have something to do with rendering the sun bloom effect, as it does not happen on my 2010 Macbook, which does not render that effect.
Compare the following image (looking away from the sun):
http://i.imgur.com/x4y8fYb.jpg
With this (looking at the sun):
http://i.imgur.com/YaLgmLn.jpg
As a sidenote, there's also noticably more stutter when walking around with VSync enabled, although not just moving the camera. Not sure if the issues are related, or if this warrants a separate bug report.
I can consistently reproduce this on my machine, with Windows 10 and an NVidia GTX 770, but aside from my Macbook (which doesn't have the issue but also does not render the sun bloom), I have no other systems to test this on.
(RM-3052 from redmine: created on 2015-12-01 by Isak L, , relates #3710 (closed), duplicates #3697 (closed))