PC shuts down while gaming !

[Duoonlol]

Hello , I have a problem with my pc it shuts down alone while i'm playing for example ( fallout 4 - cod ) , but when I use it normal it never shuts down!

I tried FurkMark (Gpu Test) it was ok until i put everything on max and then it shutted down after half an hour

I tried eveything from

-Cleaning the components
- changing Thermal Compound
- buying a new fans
( figured out it wasn't a heat problem )
then I reinstall the drivers again
after that i reinstalled a new windows !
and the problem is still there ..

my components is :

OS : Windows 7 Ultimate 64-bit SP1
CPU :[/color] Intel Core i5 3550 @ 3.30GHz
RAM : 8.00GB Dual-Channel DDR3 @ 800MHz (9-9-9-24)
Motherboard : Gigabyte Z77X-D3H
GPU (Graphics card) : Radeon AMD HIS 7950 IceQ Turbo 3GB GDDR5
Storage : 465GB Western Digital BLUE
PSU (power supply) : Seasonic - M12II Bronze ( 750W )
( new fans 120mm x 7 and 140mm x 1 )

been using it for about 3 years

 

[Duoonlol]

also another thing , I searched a lot and people say always to the shut down problem that it caused by the psu
but my psu is Seasonic - M12II Bronze , it's 750W and people recommend 600-650w when they get this problem !

 

[chilly2468]

also another thing , I searched a lot and people say always to the shut down problem that it caused by the psu
but my psu is Seasonic - M12II Bronze , it's 750W and people recommend 600-650w when they get this problem !

It sounds like it might be a psu problem if it only shuts down under high load but under low loads it's fine. If it is a psu problem it won't be a wattage problem but a problem with components inside the unit. If you can get your hands on another psu to test with you would be able to tell if it's the problem. Just because Seasonic is a really good brand doesn't mean they don't occasionally make a faulty psu or that one of their psu's won't fail at some point in time.