CPU                 - AMD FX8350 [ CPU cooler - Artic Xfreezer rev2]

Motherboard    - ASRock extreme pro 3

GPU                             - MSI R9 270 2GB  Radeon

PSU                              - Coolmaster 650M

RAM                             - Corsair Vengeance 4GB x 2

Drives              - Samsung SSD 120GB
                                      1TB Toshiba

Windows 8.1

I recently started getting random reboots on my system. By that i mean no warning, no error, just a hard reboot - black screen and then normal startup. Reasons for that could be quite a few, firstly i thought it was overheating but my CPU wont go above 71 degrees Celsius. I tried to see what conditions it doest that, i played some games like The Crew or WoW and in both cases it would happen, mostly on The Crew is 5/5 and wow 2/5. That bids me to think its high stress. I changed the thermal paste, and it didnt seem to happen for 1 night. The next day it happened on Microsoft Office 2016. 

Ram test - OK

CPU stress  test - OK

GPU stress  test - OK

PSU - fan works, voltage not checked.

Below are images of the GPU test and info

What worries me is the fact that i have another image from my motherboard, can someone tell me which component this is and why does it look like this? There is dark brown/golden substance around it, some sort of residue.

my knowledge is limited on this matter.
 

LOCATED ON CENTER under Xfast RAM

Thank you