So lots of people have been having these fps drops in game, more so in single player.
I noticed that, if you say have 60 fps with 60% gpu usage, and turn around looking at something else you get maybe fps in the 40's but the gpu usage stays the same ( where it should be going up to maintain your fps )
Well I noticed by alt-tabbing out to enable task manager just so I could see the cpu usage in game, when i tabbed back into the game I was then getting my fluid 60 fps looking at the same scene and the gpu usage had correctly gone up slightly, it stayed fine like this until i turned round, then turned back again and it was fps in the 40's with gpu usage in the 50-60% again.
Then again if I tab back out, back in and its 60 fluid again, Again until you turn around and turn back again - I could recreate this 100% of the time.

So try this yourself and see if you get the same - obviously a game problem but not sure what it points to by being perfect after tabbing out and back in, until you look at a different scene then look back again.

Other than this my performance is very good - I can run at fluid 60 with vsync on a lot of the time in single player and when fps does drop, either the gpu usage goes down aswell or stays at like 60% and not using more gpu, the fps dips for everyone appear to not even be in particularly demanding areas or scenes and can confirm that nothing is bottlenecking.
In multiplayer its fluid 60 almost constantly with very occasional dips into the 50's but again when this happens the usage is nowhere more than 60-70%.