Posted 21 June 2010 - 07:09 PM
Thanks for your input. The problem is that this noise happens at random. Sometimes it takes hours to happen, other times it's within the first few minutes of startup. One thing, it seems not to do it as much since I installed that 400 watt PSU. It's actually only done it twice in the hours since the swap (happened much more often with the stock unit).
Is there a way to tell if the heat sink is out of place, without pulling it off and re-seating it? It doesn't appear loose, but this PC does get moved around a lot. I'm always very careful, but car rides can be bumpy.
I'm not sure about the fan bearings. I've heard those go bad in computers before, and it's a totally different sound. That's more of a whine, this is more of a soft whirring sound. Like something shutting down as the power drains out of it. Except that doesn't happen, as far as I can see. All fans keep spinning and the PC keeps running normally.