Multi core CPU single thread behaviour, not achieving 100%

Question

As you can see from the attached image the CPU graph on my dual core machine is weirdly symmetrica

Answer 1

You are achieving a 50% load using both CPUs. Your program is not attached to a fixed CPU so it's switching, depending on the kernel (and other processes running on your system).

If you want to be sure your process is running on one of your cores, you have to set affinity (Example here). This way, you should see a 100% load on one core, the other one being used for other tasks.