I would try remounting the ps. I had a terrible noise from one 120mm vertical fan until I loosened all four screws and moved it slightly until the noise stopped. The noise you are experiencing is probably a capacitor inside the ps. It's not a sign of failure, just normal for some ps. If you're not rich, I would run it that way. Use the antec warranty if needed. Some are 5 years. Antec is a good company; they used to send me a free part for my super lanboy case. I just emailed them with the request, and they mailed the part at no charge. Any rattling sound should be investigated, in case it's a wire touching the fan, but mild buzzing is normal for some units.