Mate, forget word "bottleneck" in this context.
It's very dangerous word

as it leads to some psychosis. Let's imagine there are NO CPUs and GPUs equal in terms of horsepower. There will be always something stronger and something weaker, depending on application. So when one component is stronger, second one automagically becomes "bottleneck".
You get what I mean ? If you think your CPU is very fine, because o'c-ing won't raise framerate (so CPU won't "bottleneck"), what would you say having Radeons CrossFired (after graphics sub-system upgraded) ? OMG, CPU is a "bottleneck". You now go to the shop buying faster CPU. But then, when CPU will be faster, what would you say about graphic cards ? "Bottleneck". So go to the shop replacing CF-ed cards to one, stronger. But then, you will notice CPU is "bottlenecking" again, so go to the shop and upgrade CPU.... you see ? It's a neverending loop. Psychosis. Especially that people tend to observe this once new hardware family comes out to the market...
As I said - forget this word. Much better point of view is simply observing your joy from games. Do you enjoy framerate ? So it's fine. DOes your hardware meet game's requirements ? Pretty fine !
FOrget neverending greed to have something impossible (equal balance) and start enjoying what you've got