Actually, many tests and reviews (my own tests too) it has come to me that not only does Threaded Optimization improve little to no performance but changing it to "Auto" would in fact bring in lag and jumpy frame-rates due to the power of the CPU changing during gameplay. Many people would to keep it "Off" as it allows not high frame-rate but rather SMOOTHER frame-rate. It's much easier on your eyes to have 40-45fps then to jump up and down from 30 to 60. I'm currently looking into why it was made at all and so far all I have right now is "If you have a high-end CPU, it 'may' improve performance."
However, I'm going to have to close this thread. If you see a thread that is even half a year old with no replies + there is already a "best answer", then please don't answer it. Nobody is going to look at a very old thread to see what you said when it's already been answered long ago.
However, if someone in a thread made a mistake in their post, then I suggest PMing them.