By any chance have you just started the game and not ventured very far yet, are you still indoors? I ask because you WILL encounter areas eventually where you get swarmed by lots of bots firing at you with lots of visual effects onscreen. If you can get through that without noticeable problems, then I can believe it.
I have to say though, when you say you don't even know what the FPS is, as if you're not familiar with the common tools to monitor such things while gaming, it makes it look a lot like you are used to gaming at very low FPS. So I can't take this claim too seriously.
Nobody serious about playing current gen games is still playing on a AMD FX processor, one that is really only single core, and uses their crap "floating module" design to feign using more cores, and poorly at that. Games these days tend to require a lot of cores.