I've lived with a fanless PC for a few years now and most of the time it's in a low ambient. It's quite surprising how hot things can get in zero airflow, that wouldn't even get warm with even the slightest airflow.
In the same way you can run most CPUs at higher temps and they will work fine, it comes down to how long it lasts and stability. As said before in this thread PSU's often run for a while with a dead fan but the increased heat will more than likely lead to a premature death. It's the same with most components people have reported Graphics cards fans dying and the card still working for a long while even though they get hot. I can't speak for anyone else but I want to truely
solve all the heat so a top end PC will run fanless, silent and cool without
any heat issues. As such I had to get more involved with the PSU cooling solution as well as every other heat producing item..
