You dont really have a bottleneck, in crysis you will see improvements from both faster cpu and GPU, but the GPU plays a bigger part in performance in crysis. Turn off AA. Generally, to determine a gpu bottleneck, if you lower the resolution, and speed increases, you are GPU bound. If you lower the resolution, and not much happens, then you are CPU bound.
The theory is that you should be GPU bottlenecked, which you are, so congratulations!