I had been using Arch Linux 64 bit on a Gateway P6860FX for about two years, and recently switched to Ubuntu (also 64 bit). When I type on the keyboard, my left hand feels a lot more warmth than before, and the air coming out of the exhaust port is definitely hotter. (Odd, right now there's no extra heat at all...but anyway...) Only minutes ago did I discover there are ways to monitor the CPU temperature. I have no idea what it was for Arch, but on Ubuntu it's 60-something, rising to 88 when I run heavy number-crunching software for a few minutes.
There are good Q&As on this and Superuser on cleaning out dust, and ways to help the computer stay cool.
My question is: why would one linix distro run hotter than another? Is there some daemon running in one and not the other, or some device driver difference, or perhaps one but not the other sets the "run really hot" bit in the CPU's mode register, or what?
Can knowing this answer help me select the next distro to try? Given several candidate distros that are both 64 bit and meet various requirements, can we predict which ones are going to make this machine run hot?