We measure system-wide power draw from the wall while the card is sat idling at the Windows 10 desktop for 30 minutes. A reading under load comes from running the 3DMark Fire Strike Ultra stress test 20 times.
Given its clock speed advantage over the Founders Edition, it’s not surprising to see the Gaming OC Pro draw 20W more power under load. This is still less than even the RX 570, however, and Vega 56 also draws 70W more. Nvidia is clearly still streets ahead when it comes to power efficiency.