Weird flickering/pixelated image

[wknslance]

Hi guys 

I recently build my first Pc and with an Ryzen 7 2700x on an ASRock b450 Steel Legend, the Gpu is an Asus Rx 5700xt Oc with an 700W BeQuiet PSU. I´ve also build in 16gb Corsair Vengeance Ram (overcloked to 2933mhz). The problem that I  have is that when I play games like Gta V or Battlefield V i have and very weird image that locks like it flickers (extremly in dark areas). The image is also very pixelated for example even do I play on high or ultra graphic settings the game looks very bad. I installed every driver but it didnt get better. The only think  that could be the reason for this is that the Gpu   has PCIe 4.0  and the Mainboard PCIe 3.0 or that I have an  defective GPU. It look like you have an old TV and go right in front of it with ur eyes and then u see those red,green and blue pixel flickering. 

Thanks for ur help 

https://www.youtube.com/watch?v=GIBI_bVyieA