Question Help! Weird colored box screen upon startup

[RoryHankel]

When I startup my computer, it flashes this weird screen. This started after I reset my CMOS battery. The center is a solid colored box, I have seen it in purple, pink, red, blue, yellow, orange, and green so far, and the outer part of the screen shows the pixels of the display. It lasts for about 2-3 seconds before disappearing. I have tried to look up a solution, but, I can't seem to find any solutions for this issue. Please help.

 

[rgd1101]

does it work after this screen?
full system spec?

 

[RoryHankel]

does it work after this screen?
full system spec?

Yes, my computer works, I am just confused as to why this screen is showing up when I start up my computer.

 

[RoryHankel]

Found a solution. Its the XFX RX 580 GPU's Fault, it wants to load CSM, due to it's age, but, my motherboard loads in UEFI. Just set the Boot in your BIOS from UEFI to CSM, and make sure the GPU is in, so that it doesn't go back into UEFI mode, and then the artefacts screen should go away. I reset my CMOS too, a couple more times, to get the GPU troubleshooted, and finally found out that all you have to do is this.