Hi, Don't spend any further on that shit, it is not a motherboard issue but AMD graphics card issue from the factory.. caused mass recall in US, can even be done in 2015.
if you have got a heat gun you can maybe heat the graphics chip to get couple of more months out it. Even when the recall was there I visited the Apple service center and they denied. I am done with Apple for life
later via local guy got it repaired in 10k, worked for a month then again graphic glitches. Now I keep it in my room so I remember not to fall for an Apple