Normally, it should not matter whether the video card are the other two ground contacts of the 8-pin available or not (a 6-pin PCIe power connector fits into the second 8-pin port of a card). My Gigabyte Radeon R9 280 could be without the adapter but bring to life not only. The adapter is very good pereist, compared to other "brand adapters" for 5 euros and partly significantly more. Is serving now for several months! Top!