I don't know much too but I think unreal has a method or whatever which updates not every second but every operation of physics engine. If you don't know what I mean look up FixedUpdate in Unity. If you worked with unity you should know about normal Update and FixedUpdate, one updates every frame and second with fixed interval.
And optimalization, maybe turn off some graphic options or something. Like blur or antialiasing. Or create an options panel. Or my laptop is too weak to handle your game. heh