AC4 FPS issue

So for this Christmas, I got my brand new PC, and a few games like Trine 2, BF4, and AC4. BUT, I am having FPS issues with Assassin's Creed 4.

First off, I'm not sure if its an issue or just not great enough specs, but I am getting around 40-55 fps on AC4, all low settings, 1080p.

I am frustrated because I can get 70-80fps MAX settings on BF4, but low settings gets me average 50 fps on Assassin's Creed 4. What is the problem? I BELIEVE all my drivers are updated, otherwise my BF4 would run a lot worse. Is there any fix to this? Or is it just my specs?

Fx-8350, GTX 760, 16gb RAM. (and yes, v-sync is off.) 

"Optimising games to run more efficiently on PC hardware isn't important"  -Assassin's Creed 4 associate producer Sylvain Trottier

they barely optimised the pc version just shooting for all the next gen hype on all the consoles, simply put they did a lazy port and claimed that when pc gamers cant run a game they just buy a more expensive gpu


you could replace everything with low polygon count textures like we did in the old days. but i dont think your that hardcore