turbo turns "off" unused cores and ramps up the other cores to higher speeds, but you are using all of the cores so turning them off to up the other cores would hurt you, not help you.
If you could post the rest of your system there might be a better option to help your performance. If your mobo allows it, overclocking is a very good thing for what you want, but you'll need a new cooler which could run you 50 or so bucks, but the performance increase will be very big.