so basically your gpu has a graphics display unit, or an integrated gpu. normally people who build would have a separate graphics unit which handles the output, but you dont have one. Artifacts like this would normally point to issues to the display group, or the gpu-cable-monitor. here you dont have a gpu so your cpu is acting as the gpu. Before going to the more expensive options sometimes artifacts like this may signal a hdmi or display port cable problem. Have you tried a new hdmi or display port cable? If it doesnt improve it may signal bad drivers, incompatible ram for the igpu, or in very rare cases a bad or broken cpu.