I started this notice this noise coming from my mac a few months ago maybe its because I put in a new graphics card, but when my computer is idle it has a strange noise coming from it, maybe its the new fan since its bigger than the old one, but the noise sounds like a car when its idling. It could just be the fan spinning, but even when the fan spins fast that noise is still there. Could it be the hard drive or the fan? And is this normal?