Wanted to get all of your opinions but my Mac Pro 1,1 has began to make some odd fan noise from the front fans. It's quiet but every now and then it begins to make a rattling noise that comes and goes. Is this a sign that the fan is needing replacement or could it be possible something else because of heat issues. My mac has all drive bays used from 10.6-10.11 has a pc 8800gt and 32GB of ram.