VEGA 56 cant load games (video and audio glitch)

[mawerche]

New build:
-asus rog z370H
-2x8gb cl16 trident z (stock bios settings)
-i7 8700k (stock bios settings)
-VEGA 56
-old hdd that still works fine
OLD PSU xigmatek go green 700w, 9 years of heavy usage
-antec 900 3x120mm fan +250mm top fan
BE QUIET dark rock cpu fan cooler
-monitor AOC G2460VQ6

so I put everything together and it worked fine until I try benchmark or get in the game.....
the video starts glitching or it shuts down with an audio glitch that sounds like a short burst of dull singular sound.

benchmarking works on extreme presset 1600x900 but cant on 1920x1080 and it also happens as soon as i get into game (dota 2, rainbow 6 siege)

also when glitch happens, as soon as i alt-tab to desktop it stops.

TEMPS ARE GREAT !

so I assume it's old psu who can't give enough power to vega even if its 700w(who knows how much real w)....system worked WITH vega fine without benchmark/game load......

can it be faulty hdmi?

The whole system works in-game and everything with old GTX 750ti (65w motherboard power fed)

Thanks to all who finds time to answer.

 

[Greeko85]

You can always try a clean install of your display drivers to eliminate that being a cause. Otherwise its a safe bet to assume the PSU isn't up to the task.

 

[mawerche]

You can always try a clean install of your display drivers to eliminate that being a cause. Otherwise its a safe bet to assume the PSU isn't up to the task.

Thx i had generic monitor driver at that time, but anyway i ll by new psu and than i ll start experimenting, coz i dont wanna do it on the old one and maybe damage the gpu... will answer later what was the cause !