Speedfan does sometimes show anomalous readings but the +12V rail on the PSU looks to be way too high which can lead to overheating, artifacting and thermal shutdown;
Please restart your computer and check the temperatures/voltages in the BIOS, no screenshot is required just make a note of the temperatures and the +3.3V, +5V and the +12V and post them with your next reply.
NB: BIOS voltage readings.
The readings are not conclusive in the BIOS as the computer is under the least amount of load, if they are higher or lower than what they should be though it does suggest a PSU problem.