Hate to be a buzzkill but at 10 cents a killawatt you're better off on unloading them before the Antminer S7 comes out and it is a larger supply due to unloaders.
at 10c a kw/h he is good for around 120,000,000,000 difficulty.. so no worries there..
for OP..
first thing i would do with the s5s is disconnect the PWM (usually blue wire) from the fans. if you are careful you can pull them from the plug with a needle and not damage the wire so you can plug it back in later if you want..
this will set them to run full speed and lower the temps from what they would be if left alone.