Just recently bought and installed a Cooler Master Hyper 212 EVO heatsink and, though it is keeping the cpu quite chilly, the fan itself is very noisy, as if the fan blades were hitting something. However, i've checked and rechecked to see if it's hitting any cables or any other loose components that might get in its way but, from what I can determine, it seems the fan may be hitting its own plastic enclosure. Did I get a "lemon" fan? Does this happen often? What are my options?