Faulty stock heatsink or faulty CPU?

Archthrax

Honorable
Mar 3, 2013
3
0
10,510
I have been running a system for quite a few months now.
AMD FX 8350 cpu
AMD Radeon msi 7950 graphics
Corsair 600w psu
MSI 990FXA-GD65V2 motherboard
Corsair Neutron 250gb SSD
Rosewill Armor evo case

My question is, when playing games like battlefield 4 or metro my cpu will hit 90c and turn off I just learned this recently same with Prime 95 stress testing. I also have high heats around the board for gaming like 68c for light gaming like dota 2, however I idle at a low 20c.
I re-seated my stock heatsink and used new paste (pea method) but nothings changed. is this normal for AMD stock vishera heatsinks? or do I possibly have a faulty cpu? If its the heatsink any budget suggestions for replacement? I would prefer not dismantling my computer apart to install a back plate.