Overclocking EVGA 1080Ti FTW3

Hi, I’m not sure if this is the right place to ask this, but earlier today I tried my hand at overclocking my GPU for the first time with the EVGA Precision XOC program. I heard from several places on the web that 117% was the highest stable “power target” for my card. So I set it to that in XOC and all was fine for about 30 minutes. And then I started to get some weird color banding and artifacts on several places on my monitor. Then I looked back at XOC to check on the temps and they looked fine: about 45 Celsius at idle when without the overclocking it idles at 35 Celsius. Anyway so then I disabled the overclock because I was afraid something bad was happening to my card.

My question is what caused the color banding and artifacts on my monitor? My card has more than enough power supplied from the PSU for the overclock and the temps looked fine.

Thank you for any help