I've searched around the forum and read about this, but I'm still not satisfied. I have a 13" uMBP (2009), about a month old. It runs warm and as I understand it, this is normal. I was curious about the fan in it, so I downloaded iStat pro and discovered the fan running at 2000 rmp, also normal. To test out the exhaust, i ran "yes >/dev/null" in two separate terminal windows and pushed my CPU to 100% for each core and watched the CPU temp. rise. Now, my question: when should the fan normally ramp up from 2000 rpm? I watched the temp get to about 95-100C before the fan finally went up to 3000rpm. Should this concern me? I understand Apple likes the quiet and thus sets the fans to perhaps not react directly with temperature increase. But should there be such a delay? Right now, I'm running Fan Control (http://www.macupdate.com/info.php/id/23137) because I prefer my fan to increase speed as the temperature increases in order to keep it cool all the time, rather than react to a really high temperature and try to cool it after the fact. Any ideas/comments? If you have a uMBP, how long does it take your fans to respond if you run "yes >/dev/null"?