The GPU is the issue xd/ artifacts via its memory clock frequency.. Bad card! You can tweak it via some 3rd party software but I'd say time to look for a new graphics card for the build! Does problem not pop up at startup? does it creep up over minutes of use?? Explain the issue more, Please! It might just need new thermal compound on the graphics processor die! What have you done so far to troubleshoot the problem?