I have a mid 2011 21.5" iMac with i7 upgrade, recently I installed a 3TB hard drive and a 240 GB OWC SSD beneath the optical drive. Its been working what I consider to be quite normal with the exception of crashes caused by a "wake from sleep" issue which I haven't figured out yet. I'm hoping the next upgrade in Mavericks will fix that as it seems to be a fairly common problem. Anyway for the past two days the system fan has been going on and off to the point where I am hearing it and its bugging me. I never noticed it running before unless doing some heavy graphics work. I installed a temperature monitor and the graphics card is running around 70c, when it gets up to 71 the fan seems to kick in and then once it drops back to 70 it turns off. The CPU temp is 62c. I a little concerned that the SSD might the blocking some of the cooling air getting to the GPU heatsink. But I have had the SSD installed for over a month and this was not happening until yesterday?? Needless to say the top of the iMac is pretty damn hot! I've checked Activity Monitor for the energy impact and the only program that is really using resources is Parallels as I run a window with Windows 7 all the time. The average energy impact for Parallels is 26.63. I've tried shutting it down but the GPU temps have not dropped below 70. Any suggestions as to what might have changed?? The ambient temperature in the machine is 37c. Here in St. Lucia the average temperature is about 30c or 86f. And its not like the temperature in my office just suddenly increased, its been quite cool actually.