2 things off the top to start with, check what caps line up with that area in case the motherboard had some cap(s) go AND get a can of ' component cleaner ' from an electronics parts store. Most component cleaners need a well ventilated area due to the chemicals and will have to dry before trying the card again as they ' melt ' excess oils and flux leaving a nice clean board ( or clean out old variable resistors ) usually with out any harm to the black silk screen. If the card isn't under warrenty, feel free to call it time to change the thermal paste under the heat sink too.
Other than ' cap spray ' from when an electrolytic cap goes with out leaving the board, not a clue what could cause that.
