Asuka{eve}..
Here you go.
http://www.amd.com/us-en/assets/cont..._Rev04_ENG.pdf
Take that link, and you will see the absolute TOP end of your proc is 80c. Would I run it anywhere near that, hell no. However, chances are unless you have mounted the heatsink incorrectly you are fine. Would I OC that system? Not a chance.
If you really are concerned about it go get that sink Lasereth mentioned. He knows his shit.
BTW, Motherboard monitor is just using the same multiplier your mobo monitor is, so it should be almost identical in temperature readings. Is it correct? Who knows.