Guild Wars 2

Sry about my English

my pc spec :
1. AMD 8350
2. Gigabyte 990FXA-UD3
3. VGA : Sapphire 280X Toxic (Driver 14.4)
4. RAM 8G
5. PSU 850W
6. SSD Samsung 840Pro (install gw2 inside)
7. window 8.1 pro 64 bit (license) and lastest updated

my pc alway auto-restarting when i killing mobs or players in zoom in view.
i.e. like moving scorebar to maximun zoom in on mouse and use single skill and aoe on mobs or players in wvw.

but in normal view it seem fine. i can run with map zerg and fighting with other map zerg without auto-restarting.

any suggestion ?

thx for info guy

now i using AMD Phenom II x4 955 BE and planning for buy new CPU ( AMD FX 8350 8 cores 8 threads )
i dont wanna waste money for nothing

thanks for reply