Lol.

Its true that too cold is not good for the CPU, but you probably won't acheive those temps without spending a really huge sum of money. And you definately won't reach those temps on anything thats easily available to the general consumer/enthusiast.

TEC coolers may not be that easily available, but it still does not reach those temps . I'm not an EE, but given that CPUs are overclocked for fun on LN2, and that the best overclocks are NOT on lowest possible temps (these guys claim that a few degrees over N2 boiling temp is best), I'd say I wouldn't worry about your 15C (which is a temp I'd love to run my comp at )

 

15 degrese is nothing to sweat. And as for the AS5 burn in, it does take some time for it to kick in. I believe that AS says that it may take a 1week-1month for your AS5 to be at its prime. I would give it a little while and see what temps you are achieving after some normal wear and tear.

 

I don't think it has anything to do with time, more to do with how often your CPU goes in and out of the heat cycle. I think if you took the time to get your CPU temp to max, shut it down and let it cool to room temp, rinse and repeat 300 times, it'll burn in by then. It might take you a few hours to do so...