The power draw will depend upon the brand and model of the card.
Some of the non-reference design cards will draw more power. For example, the Palit GTX 1080 GameRock Premium 8 GB will draw, on average, 210 Watts during gaming whereas an NVIDIA Reference Design GeForce GTX 1080 8 GB GDDR5X Card will draw, on average, 166 Watts during gaming.