Question HDMI cable works fine, but DP cable causes horizontal line when booting, but works normal after that ?

Sep 26, 2021
I have Asus monitor

and Asus desktop (ASUS - ROG Gaming Desktop - Intel Core i7-11700KF - 16GB Memory - NVIDIA GeForce RTX 3080 - 2TB HDD + 512GB SSD )

My brother changed the case to NZXT and replaced the fan with corsair 240 liquid cooler)

With the hdmi there is no issue at all.

But once i change to Displayport:

The initial boot it shows horizontal lines then wont show windows logo and straight boots to the end where i put my pin to log in.

When i restart , it boots as normal.

Only when i completely turn of the pc and turn it on this happens.
I have tired many things like changing dp cable. Turning off gui logo, windows logo, enabling xmp. etcs)

My graphic card is Nvidia rtx 3080 and i dont think its the issue with it because game runs perfectly without any tearing.