Question screen goes black for 1 sec and resumes without error

[mrtiwaz]

hello.
i started getting this problem..
when i start up the computer it shows the login screen for 4-5 sec and then the screen flashes black and goes back to normal. no error the same problem happens when i open any games and/or tap in/out it only flashes for 1sec

things i have tried to fix or find the root:

different screen/cable
other gpu slots both PCI-e and display .
gpu stress test for 3 hours (everything fine)

did a memory test (everything fine)
cpu stress test (everything fine)

removed all drivers and reinstalled (no change)
reinstalled windows 10 (same [censored] clean pc)
tried changing power cables to a different PSU output/gpu (no change)

spec:
AMD ryzen 2700x + Bequiet dark pro cooler
asus rog strix x470-f mobo
g.skill tidentx 3000mhz 16gb
asus rog strix 1070ti
corsair RM 850w gold psu
Windows 10

 

[RARRAF]

you say different screen cable what are you saying HDMI/Display port or what ???
what connection's do you have on screen ??