Current processors will throttle themselves back to lower power consumption and heat. Given the need for the CPU to use all its cores, then the additional cores will turn on. For instance, when not setup to run on all 4 cores, my processor would normally run off of 2. Most common programs will not have a high need to run current processors @ 100%. Another example would be that when I am playing WoW or Sw:tor, I utilize at most, 15-25% of my processor. I7-920 @ 3.8ghz. Hope this helps. Some additional information about your processor might also help if this is not the case of your processor. If you want to ensure that your processor is running correctly, programs like Pime95 or CPU-iz, and Speedfan will show your hardware usage. Good Luck!