We measure system-wide power draw from the wall while running the 3DMark Time Spy stress test for 30 minutes.
As for total system power draw, it's hardly a surprise to see the Phantom Gaming on level pegging with the other 5600 XTs in our chart, with barely any difference between the ASRock, Sapphire and Gigabyte models. The MSI Gaming X does pull around 20W less, but it also runs with slower memory.