http://www.guru3d.com/files-details/gef ... nload.html
Apparently this fixes ropey performance some people have been experiencing with Kepler based cards (600/700 series), for instance people are reporting FPS increases with The Witcher 3:
http://forums.guru3d.com/showthread.php?t=399569
Also it includes new features such as Windowed G-SYNC:

ULMB activation via CP:

G-SYNC with V-Sync OFF (similar to Linux drivers posted here? http://forums.blurbusters.com/viewtopic.php?f=5&t=2188)

