I made sure there was no problem with the cables today. That visual error is not the only problem though. There is a problem with the boot sometimes too. And I noticed today that when the boot problem happens it's not the GPU's fans that spinning at the full speed but the other fans. I don't know if it's CPU's or case fans but it's not the GPU's for sure. So I'm thinking it's probably the Motherboard with the problem but I'm gonna try your suggestion with the TV today. Windows fastboot was never enabled before and I turned that on today, It realy helped with the boot time. That white line fades a bit sometimes but comes back after couple of hours but It's not visible right now, hope it never comes back lol. Anyway, thank you for your opinion on this as it somewhat enlightened me for some reason.