Is it normal for some games to simply not utilize what all your cpus and gpus have to give? I have an i7 3630qm and a gtx 660m and when I play tropico 3 my gpu usage hovers around 90% and my total cpu usage is around 15% and I still get frame drops as low as 35 on ultra settings. I've been looking around and it seems that some games (especially older ones) have poor optimization. I also have the same problem on most older source games where I get 40% gpu usage and cpu usage is 12-15%, but still get lowered frames. Everything is set on high performance btw and I make sure to check prefer high performance for gpu in nvidia settings.
Just wanted to see if my hunch is correct for these cases, which is that there is no bottlenecking, but some games simply will not utilize 100% of your hardware for whatever reason, newer hardware, etc.