I noticed when doing a fresh install of 10.10rc (previously using 10.04LTS) that my laptop fan actually changes speed and keeps the laptop significantly cooler

I noticed when doing a fresh install of 10.10rc (previously using 10.04LTS) that my laptop fan actually changes speed and keeps the laptop significantly cooler temps than 10.04LTS. Laptop is a Toshiba Satellite. I believe 10.10 is also more effecient when viewing system with Powertop. I am happy that I switched to the 10.10 rc. Is there a great difference between the rc and the final version? I noticed the rc version is slightly larger in size.