Weird sound?

So basically it's sounds as if something is touching the fan and it does it for a couple seconds. It does it once maybe every ten minutes. Here's the weird thing, it only does it in Mac. In fact not really even Hackintosh, it does it inside Mac in VMware as well. It never does it in windows. It's a very odd noise I can't tell if it's the fan or hard drive or what it's hard to describe