Power Draw
We use Nvidia PCAT to measure power draw of the graphics card only, with readings from both the PCIe slot and the PCIe power cables combined into a single figure. We use A Plague Tale: Requiem (4K/2160p) for this testing.
As for power draw, both the Steel Legend and Nitro+ have higher power draw than the Hellhound, coming in close to 190W, while PowerColor's card stays just below 180W. That's only a small difference though, and probably won't factor into a final buying decision.
Performance per Watt
Combining the power draw values shown above with the performance data, we present performance per Watt for each graphics card tested:
Those power draw differences do result in some change when looking at performance per watt, but again, we're talking very fine margins here.