That is nothing new, most of the sensors on the mobo are useless anyways, its not unusual to be off by 10C or more and the voltage sensors are just as bad.
Really, your CPU isn't overheating, just running kinda hot (if that temp. is in fact correct...) so unless its at stock and behaving like that and you want to OC I wouldn't worry about it. Unless you're talking like 100C+ (which is impossible since the over temp. protection will kick in long before that) high temp. won't damage the CPU, at worst you'll get some instability/BSODs + occasional system shutdowns til' you get better cooling. I really doubt its running at that temp. unless you totally screwed up mounting the HSF though or the fan died or there is no case ventilation at all.
If you really want a accurate temp reading I'd buy something like this here:
http://www.virtual-hideout.net/revie...00/index.shtml
there are better ones out there of course with a wider range of temp. sensing which is really nice if you ever go phase change but the price starts to go up quickly too.