try dropping the resolution (keep other settings the same) in skyrim and see if your FPS goes up. If it goes up you have a GPU bottleneck (unlikely). If FPS stays the same at the lower resolution you have a CPU bottleneck.
What...? Running a lower resolution makes it MUCH easier to run, so obviously the frames will be higher. I'm not sure what you are talking about there. A much easier way to check if its a CPU bottleneck, is seeing how high CPU usage is, while playing a game. If maxing out at 100% while your GPU is at like 60%, then its a CPU bottleneck. If its less than 100%, then you might have some issues elsewhere.
Also OP, about Skyrim. Its been noted that Skyrim only utilises two cores, meaning that GPU usage will often be lower than 100%. I hit around 60% GPU usage in Skyrim.