Question : Problem: Power Supply Fan spins too fast

Yesterday My Ultra X-finity XF600 power supply's fan  suddenly  jsut started to spin faster.  I'm not sure if it automatically does that if inside the case gets warmer.  But inside my case its not warm at all,  because theres good amount of space for air to travel.  Its at normal temperature.  The power supply case temp is rather cool  and I'm not running heavy application.  Even if I do run heavy applications like games,  the fan still runs normal speed before this.  

I mean its pretty loud, it not scraping or anything like that,  just spins faster and gets noisier.  I jsut finished cleaning  the inside of my case,  somehow it got a bit quieter, but still not back to what it used to be.  My computer is running fine,  everything works fine.    I even unplugged the case fans except the cpu fan.  Yep its the PSU fans.  

Is it automatically controlled?  

Answer : Problem: Power Supply Fan spins too fast

You can try blowing them out, yes.

If that fails to do the trick, try some graphite lubricant. The graphite lube is a dry lubricant that comes in a can like WD-40 or LiquidWrench, but won't be a messy liquid that would end up all over your case. Spray some in the bearings of each fan and see how that does for you. If that fails to do the trick, then replace the power supply, or the power supply fans.
Of course, if the power supply is under warranty, you might be able to fore go all of this and just take it back to the store.