Bad performance in Borderless Fullscreen Mode

[Elysium]

This isn't an answer, however games work best in full screen - this one included. If it's not, that might point to a larger issue > Drivers, Vsync settings, frame buffering, pre rendered frames ahead(this one in particular might alleviate stuttering if raised).
If the game degrades over time - and we can't isolate it as a game only issue - than it's a memory filling issue e.g. GPU running out of memory. That's suspect though, I'd be hard pressed to believe that a single monitor setup at 1080p takes all 2GB.

What are your in-game settings under system configuration and what of your Nvidia control panel settings?

My Nvidia Settings are all default and using the 326.80 driver.. MB drivers up to date also and Windows update full

My in game settings are all maxed out except for Shadows Normal 1024p.. enabled LOD and Occlusion Culling for better performance.. 1920x1080 60hz

My framerate is really good all the time.. 60 fps even with lots of people with some drops when there is extreme action on screen.. but the stutter is the main problem.. in Fullscreen the game have less stutter but the camera movement isn't smooth that's why I play in Borderless Fullscreeen