Really funky temperaturess with HW Monitor

I recently upgraded my system and got this:

AMD FX 8120
EVGA Geforce Ti 550
8 gigs RAM
AsRock 970 Extreme4 motherboard

The CPU temps when running something like Guild wars 2 jumps from about 45C idle to 65C in-game on the processor and this worries me. I downloaded HW monitor to watch the temps closer and noticed something really strange. There's an "AUXTIN" temp that literally jumps from 50C to 128C and anywhere in between within seconds. I have no idea what this reading is or where it's coming from. How would I find out? Here's a screenshot of HWmonitor with the high temperature. (i took this picture with no games running)






:::::Update:::::

I shut my system down and cleaned all the fan housings and the cpu temp hasnt gone above 60C since (during Guild Wars 2). As for the weird 128+ reading I get, during gaming, the temp reads normal (45-50) but idling the temperature reading goes absolutely nuts. Bad sensor?

Some AMDs have bad low side temp sensors. Just worry about the high side under load. Run Prime 95 for 10 minutes.

And Use CoreTemp for AMD temps, it's what folks recommend, unless things have changed with the newer AMDs.

The odd temp is some mobo sensor etc. Don't worry about it.

I have the same board. TMPIN3 and AUXTIN are fake temperatures, nothing to worry about. When I put prime95 the AUXTIN drops from 120C (usually) to 8C