Once in a while, in random instance, a portion of my screen (maybe half of it) will blinking black patches for a milisecond. This happened even when I'm not in a game, e.g. browsing Windows Explorer, using internet, etc. I can't seem to track when and why it happens, but it seems to happen more frequently when watching YouTube.
EDIT: This is what I mean by blinking black patches. Watch it slowly in the first few seconds... http://gfycat.com/SkeletalAdoredJanenschia
Might only be tangentially related, but there's also this weird continuous blinking every time I open this website: http://dragonporn.ldblog.jp/ (despite the name, it's not a weird fetish and 100% safe for work)
Here's a short video depicting what I meant: http://gfycat.com/CoarseQuarrelsomeDarwinsfox
Curiously other HTML5 video seems to be fine.
It's not exactly the same blinking with the one I've described before, but I'd lke to know if it's somehow related.