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 for 30 minutes.
At first glance, I couldn't quite believe the power draw when using the OC BIOS – but after triple-checking, these are the correct figures, with total system power draw matching that of the RTX 2080 Ti. Clearly, ASRock pushing the clock speed as high as they did has a very detrimental effect on power draw, resulting in significantly worse efficiency for this Navi card.
Again, the Silent BIOS is much improved, with a 50W reduction in power draw versus the OC BIOS. This means the Silent BIOS barely pulls more power than the reference card.