I was wondering if there is something I missed after installing my GPU after RMAing the original XC3 Ultra RTX 3080 12 GB. The original card was stuck on these weird lines while booting, and also was having overheating issues with one of the fans being dead. I just received the RMA replacement GPU yesterday. After installing the new GPU from RMA, the first boot up showed none of the weird lines like I saw with the original card. New card is working fine, as I tested it playing Cyberpunk 2077 and PUBG after setting the fan curves in Precision X1 and confirmed all fans were working. After that first boot, I am seeing the weird lines screen again briefly then it goes straight to the user login. I made sure to use DDU to do a clean reinstall of the GeForce drivers. I also ensured the GPU and all power and display cables were seated properly. I am not sure if I am missing another step since the installation or some other issue is present.
 
I am using a MSI B450 Gaming Pro Carbon AC mobo, with a Ryzen 5900X, 32 GB Trident Z RGB RAM, and 1000 W EVGA P2 PSU. The image below is what I am seeing on boot up since yesterday.

Thank you for whoever responds with the troubleshooting! Greatly appreciate it!

the_Scarlet_one
Is your motherboard bios fully up to date? If there is an issue while initializing the PCI slot, it may be a bios issue that could possibly be solved by a bios update.

I would start there since it happens with the bios load, and then clears up during user login screen, and then work outward from there.

Yes, I made sure to have the BIOS updated to the latest edition. I'll try reflashing the BIOS and see if that helps. Thanks!

I tried reflashing the BIOS. While the XC3 GPU was still slotted in, the BIOS wouldn't load to the screen and it held the weird lines screen as pictured earlier. I swapped back to my old GPU and was able to reflash successfully, and then swapped the GPUs out again. Upon start up, I'm still seeing the weird lines.

harleyroadking
May sound like a dumb question but have you tried replacing the cable? Something like that happened to me and it turns out that it was just the cable I was using.

Not a dumb question. I'll stop by Micro Center tomorrow and pick up a new DisplayPort cable. The one I am using I did pick it up previously from Micro Center and had worked with my original ASUS Turbo GTX 1080.

No luck. Same lines that appear on boot up before the computer loads to login screen after replacing the cable with a brand new one.
 
Edit: I tried booting up with just the Displayport cable and not the second monitor's HDMI cable. Looks like I need to swap the other HDMI cable. Thanks everyone!