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 Resident Evil Village (4K) for this testing.
Using the Performance BIOS, with its 340W TGP, results in power draw of the GameRock OC hitting 325W. This makes it the most power-hungry RTX 4080 I've tested, but it's still a bit below the rated TGP, and still draws less power than the RTX 3080.