So, recently, I've been having a bit of a problem with my PC, really noisy/loud fan issues. Typically, it would crank up during times of processor stress like renders and having too many programs open, which always seemed normal to me. It has done so that way for years. Lately, in fact, ever since I updated to Windows 10, the problem has worsened. Now, I just figured that Win 10 ran "hot", as in, it's a more complicated OS, and has more going on in the background than Win 7 does, so it makes sense that the problem would worsen.
So I got it into my head to try maybe clearing some dust away from the intakes, which is my standard procedure for trying to help the fan blow better, though do not reduce the fan noise noticeably. Apparently, it has been a few months since I last got to them and they were a little more clogged than usual (I also have a cat that sheds) See before and after pics. Then I decided to step it up a bit this time; Unhooked the entire machine, opened it up, and just attacked the entire thing with a vacuum, focusing mostly on the 3 fans; 2 in the back, and the 1 sitting on the processor. Then I hooked it back up and listened. Not a peep. Problem solved. The thing runs like brand new (nearly 5 years old). Then I loaded up my most complicated render and ran it full bore for a straight hour. Nothing. Whisper quiet.
This is the lesson: Do not suffocate your PC. It seriously impedes your computer's ability to function.
WARNING!: A lot of people used canned air instead of a vacuum. Be careful if you use a vacuum, as I have witnessed some people fry out their motherboards with a static charge from using a vacuum. To protect against this, I got a cardboard roll and used that as a vacuum head (paper doesn't conduct electricity). Seemed to do the trick. Good luck!