Black screen while gaming

[MaxyPlayer]

Hi,i recently bought a gaming pc (gigabyte rx 480 G1 gaming 8gb, i5 6400, h110-s2h, segotep nuclear aircraft 520W 85% 80+) and after 1 min of crysis 3, 5-10 min of gta 5 and others, my computer screen goes black,or gray,or... and i can just restars(if i do it imediatelly after the screen goes black) and power off, and i hear a sound when it goes black....the temps are not over 45 at the cores and not over 62 at the gpu (in crysis 3,didn-t look at the other games)... is here a problem with the 520w psu? the gpu has a factory problem?what should i do?...

 

[popatim]

It very well could be the power supply. Ones that come with the case free are not often very good ones and the Rx480 likes power.
Can you see the exact make and model# of that PSU?

 

[MaxyPlayer]

SEGOTEP Nuclear Aircraft Carrier 520W, 1x120mm, modular, H9 PLUS+

 

[popatim]

That claims to have 25amps on each of the two 12v rails so that should be enough though I am still skeptical of it. Even Google could not find reviews of it though it seems to get decent user ratings. Can you see if the PSU fan is spinning and if it, or the cables to the GPU, feels hot when the pc shuts down please. Thanks.

 

[MaxyPlayer]

The PSU is working fine,the cable is not hot,but i have seen that the blackplate on the GPU is hot as ... but the temps are normally...