Aside from my sarcastic comments... I find it hard to believe "burning in" memory or any computer componant helps. Elecrical componants wear just like moving parts wear. Well... not JUST like it... but... electronics have a certain life expectancy. The average CPU might last 20 years if it's taken care of and kept at factory specs, but who's gonna be using thier current CPU 20 years from now? Increasing the voltage of the CPU increases the signal strength, so at faster speeds, the processor can still understand the info being sent to it. But you're also increasing electrical pressue (voltage is defined as electrical pressure) which will break down the logic gates faster. So by increasing voltage in order to overclock, your CPU may last 5 years instead of 20. I don't know about you, but I don't plan on using this CPU 5 years from now.
Really, the only place heat comes into the picture is in the conductivity of the connectors... hot "stuff" doesn't conduct electricity as well as cold stuff... which is why a CPU may become unstable as it's temp increases... it gets hot enough that the voltage supplied is no longer enough to create a clear signal because some of the voltage is lost in order to overcome the increased electrical resistance of the hot "stuff"
The moral of the story is... useage breaks down the componant... it doesn't improve it.