gtx970 Zotac GTX 970 artifacts after I turn on my PC, but the artifacts disappears soon after.

[xxxdragon69420]

Recently I bought a GTX 970. The exact model is zotac 970 amp extreme core. When I tested it, it had extremely high temps and it was thermal throttling. I thought that the high temperatures caused the artifacting. I opened up the GPU and it basically had zero thermal paste applied. I changed the thermal paste but the artifacts still persist.

 

The artifacts appears whenever i shut down my pc and turn it on. When I restart it the artifacting doesn't appear. After being on for a while some artifacts appear like in the photo I attached, but disappear after a bit of time. The artifact after I turn on my pc look similar to the photo I attached, but instead of groups, the dots appear randomly and alone. The artifacting disappears after the windows lock screen. The artifacts don't appear without drivers. I am 100% sure it's the gpu's fault. The problem also happens on other computers with the 970 installed.

 

Is there any way I could fix the gpu so it wouldn't artifact.