New build, 120C Aux temperature?

Hi, I just built a new computer about a week ago and I've only just started having problems with this weird aux temperature in speed fan.

This is my build.


MotherBoard: ASRock 870 EXTREME3 AM3 AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard
Processor: AMD Athlon II X3 450 Rana 3.2GHz 3 x 512KB L2 Cache Socket AM3 95W
Ram: GeIL Value PLUS 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10660)
VideoCard: Sapphire 6850
PowerSupply: Antec earthwatts 650W
Case: Xigmatek Xigmatek Utgard Window CPC-T90DB-U02 Black Steel / Aluminum and Mesh Bezel Computer Case
HardDrive: Spinpoint F3 500GB
DVD: Standard sata DVD

The problem is, my computer has been freezing up and then I have to force it to restart. The computer stops responding, and then the mouse freezes up. I've had the little loading thing on the mouse continue to spin before though, so every thing isn't frozen.

And I have this temperate in speedfan. AUX 120C. It's also in HWmonitor, and Everest. I just lowered my CPU vcore from 1.4V (it was on auto, and this is what it was at) to 1.35V and the temps went down about 20C (now at 95-100C)

Any one know why it's so high? Or what AUX is? I've touched every thing in my PC, nothing seems hot.