Hi Mazuro,
I think this could be caused by two problems. Overheating is likely, but the PSU is a definite possibility as well. Please list your system specs from Everest and post the specs of your PSU located on the side as well.
Also, download SpeedFan and RivaTuner. When you are playing a game, minimize it and take a look at your temps and voltages from SpeedFan and your GPU temps from RivaTuner. Please post these as well.
I think this could be caused by two problems. Overheating is likely, but the PSU is a definite possibility as well. Please list your system specs from Everest and post the specs of your PSU located on the side as well.
Also, download SpeedFan and RivaTuner. When you are playing a game, minimize it and take a look at your temps and voltages from SpeedFan and your GPU temps from RivaTuner. Please post these as well.