the defect in the 2011 MacBook Pro comes from the lead-free solder that's used to connect one of the processing chips to the main circuit board in the computer. According to the complaint, the frequent changes in temperature that occur while using the MacBook Pro cause the lead-free solder to crack, which in turn causes the graphics issues as described above.
The problem, which first emerged in February 2013, escalated throughout 2014 as more and more owners of the affected models began to experience issues. While playing games, watching video or performing another graphics-intensive task, users have witnessed their displays distorting, or sometimes going completely blank. Rebooting the machine temporarily resolves the issue, but it almost always returns.
Eventually, many users found that their MacBook boots to a blue or grey screen. Currently, the only permanent resolution is to get a replacement logic board, but that can prove quite costly without Apple Care. It's believed that overheating is to blame for the issue.
For repair this issue , wu could just disable the faluty graphics card (GPU) and use intel graphics instead