hi all, have an asus commando MB, and for a while now i hear the fans in my system slow down when my comp is under load ? so today i decided to install asus probe 2 and the readings are 10.8V idel and 10.2V under load ?
the psu is a 500W 21amp  and is now around 7 years old
 
im pritty sure its going to be the psu on its way out, but i thought id just check, as im not sure how accurate the asus prob is ?
 
Cheers
mike

 
Not very accurate but still    
I have no doubt that your 7yo PSU is getting very tired.  If it is bad enough to slow your fans down already, I would change it before it dies and takes other parts with it.

You could confirm the low reading with a multimeter, but it sounds like it's time for a new PSU.

Borrow a multmeter and check the yellow wires.  They should be 12.0 volts plus/minus 5% or 11.94 to 12.06 volts. I might go 10% if everything seems to be working, but no more.