I have a mid-09 MBP and just recently upgrade to Yosemite. I was importing a movie into iMove 8.0.6 the other day. I hardly use iMovie but I know that in general when a computer render videos the CPU can hot pretty fast. I was expecting the fan kicks on pretty soon but after 5-6 minutes into a 10 minutes project I have yet to heard the fan. I opened up iStat Pro and was shocked to see the CPU was up at mid 90s climbing and the fan was hovering around 2500RPM. It ran up to 3000ish RPM when the movie was done. I'm wondering if anyone has experienced anything like this before. I know the fan is working fine before I was just watching some online videos and the fan is already up at 3100 when the CPU sitting at 80C.