My fan noise is now getting louder and louder. My computer is about 6 months out of warranty now. I took it in about 2 months after buying it complaining of a fan noise, but of course they couldn't hear it in the apple store over all the ambient noise. I have read up for a few months and it seems to be be an optical fan problem. My question is, how much will this cost to fix out of warranty roughly? Is it as simple as them installing a new fan? All the temps/speeds of the imac are normal on Istat. The noise is just really annoying and very noticeable. Any advice appreciated.