53 is high for an idle temp...if you don't have things like aero spiking your card....actually your 260 gtx should lower its clock to a low power state....that keeps the temps up to 20c lower then even the lowest clock on evga precision
Anyways....i wouldn't load the 260 gtx much past 60c though as thats where my card actually tops out....
On another note why did you not google this...such a pointless reason to sit and ask questions you could spend 5 seconds in google to find out...