How old are you? In my teens we constantly lied about our gaming performance when we were 16yo, 17yo. So your friend telling you he is getting 80fps might be a lie.
Even if it isn't a lie, there are many issues at hand here: What were the exact settings, what resolution, what part of the game was this measured at, which program do you measure fps with, etc...?
What OS do you and him have?
Like there are so many variables here, just 1 different setting and he could be getting 80fps with low shadows, and you have shadows set at max and you may be getting less fps and again which part is this tested at and what program? Do you both use fraps or are you using different programs?
I don't believe your GTX 980 is under performing, I think you are comparing apples and oranges and coming to a conclusion with no basis in fact.