Underclocking? That is usually done by underfeeding the CPU which can produce errors due to there simply not being enough power available. However, I do agree that overclocking is a little tiredsome as that is very prone to messing up and becoming unstable due to you over feeding it with energy and it goes hayware, burning out and an array of problems.

"Stock-speed" is the right kind of cool, perhaps the tiniest fraction just above, so it is humming perfectly.