You mean the 950 or EE? If so, then no. The 920 or Xeon variant overclock very well. As for leaving the CPU overclocked, you can enable a power saving feature that allows it to lower the multiplier and conserve power and heat. Though I never use it since I'm always utilizing my computer. Some users also lower their overclock during different times of the year (Summer mainly) due to the heat output of these chips.