I don't think you need a 3 pin cable. All RGB headers have 4 pins in width as well as on this graphics card, but some are non-addressable (4 pin) and some are addressable (3 pin). The pinout is different in the two types, but as long as you plug two compatible ends together (3 to 3 and 4 to 4), the cable has no effect. But 3 to 4 or 4 to 3 does not work!