well, ive learned overtime that the cpu thermistor is usually wrong. the amd athlon/duron core is able to withstand i think like 65C without dying...i may be wrong
but anyways, unless you are living near the equator and your computer is next to a heating vent, your ambient temp is probably not more than 35C, or it shouldnt be anyway if you have decent enough ventilation.
at any rate, if it was 35C, then 50C is perfectly fine because you have to factor in some error..either + or - some
chances are its probably a little hotter than it says, but does it work? if yes, then who cares. if no, then maybe turn it down a little
you are fine though man...leave it on for a while and if there isnt a problem, you're all set
edit: actually, now that i think about it...cant the cores stand something like 80C without frying?