There's no such thing as a 7400k, just 7400. I can also see how it would average 40 FPS on the lowest preset @ 1080p with that spec since I've seen such hardware run it in outlying desert areas at mid 40s, then mid 30s during combat. It would be even worse in Alexandria. Like it or not it's a demanding game, and requires good hardware to get good results.
That said, I have found it helps to turn Vsync off and use Borderless screen mode.
[video="https://www.youtube.com/watch?v=CuqyWoilCGM"][/video]