Answer to: Fans Running HighHi, depending on the age of the device in my case 2009 MacbookPro, it could be the CPU/GPU thermal cooling might be the cause. As time goes on the constant heating up of these two can cause your thermal grease/paste or pads to dry up and loose effective cooling, the heat does not transfer as efficiently so the temps rise, the fans kick in, now of course certain software Flash ect. can cause the CPU/GPU to become taxed also but in my case after replacing the thermal compound on my CPU/GPU everything ran like new. Just a suggestion. Good luck.