What's going to happen now? I told him it may overheat or reduce the CPU life but he said its barely in use or in full load. Anyone knows what are the possible consequences? He said he's been using once in awhile for at least 2-3 months now.
Yea, the first posting was right. When you don't apply a thermal paste, your notebook temperatures will be higher than they are normally supposed to be. The thermal paste helps to keep the temperature down. As a result from no thermal paste, if you're exceeding thermal temperatures, then it can be quite bad; fires or melting the CPU or other components.
While your CPU may never exceed the thermal maximums if it's on low load, that's no reason not to apply the thermal paste. You ALWAYS want the temperature to be as low as you can properly get them.
There's no reason not to apply a thermal paste. If it were expensive, it might be a different story but it's really cheap and does more than what it's worth. Your friend simply doesn't know as much as he thinks he does, or he doesn't realize that it's still a good idea despite you're not exceeding thermal maximums or whatnot.
Yes, they attempt to do that but in some situations, it doesn't work as intended. My laptop has shutoff more than once due to overheating (primarily the CPU). The idea sounds great on paper, but believe me, it doesn't work as well as you expect it to.
And it will typically shutoff if it can't stop itself from overheating. But the TJ Max is 100 and Intel says to stay under 90, so if you're somewhere in 90 <= temp <= 100, then you could damage it without intending to and still operating within the design specification.