I am thinking about buying this mac pro 3,1 but the owner says that it is have these issues "I've boot from the factory CD, replace the video card, check the ram, did a SMC reset and a PRAM reset and get the same issuse : Rainbow sprites on the screen and the system looks up.. but if I place a full size house fan blowing on it , the system runs over night, rock steady, copying files, wiping drives, streaming Pandora.." Any idea of how big of a fix this could be the price is good I just dont want to get it and then spend tons of money fixing it if it is a mother board issue.