How much does FOV affect performance on console?

I'm currently playing on an Xbox One with 100 FOV. Very frequently I'll dip into about 30 fps in gunfights and it is extremely distracting. Will lowering my fps help to fix this problem or is it just this game is poorly optimized now for last gen consoles? I used to play back in season 1 and I don't remember the fps drops and lag being this bad.