Weird partial screen flickering after upgrade to 14.04

This worked for me: http://ubuntuforums.org/showthread.php?t=2243912

Enable Force full screen redraws on repaint option in Workarounds

I had random flickering similar to this (eg. part of webpage flickered in Firefox (hardware acceleration = on), or desktop icon flickered when deselecting it) and this seemed to fixed this issue.

I'm using Nvidia drivers 340.58, Lenovo Y500 GT 750m (single, no optimus, IntelHD disabled).

It's a bug in Compiz. If it affects you then you should go here and click on "this bug affects me".

There is a workaround but it can make the system a little bit slower.

Install CompizConfig Settings Manager, then go to Composite and disable Unredirect fullscreen windows.

I have installed nvidia-331 (331.38-0ubuntu7) drivers and for few days now I have not experienced any flickering so probably it was a problem with the drivers (xorg-egders version 334 or recent 337 )