We measure system-wide power draw from the wall while running Cyberpunk 2077 for 30 minutes.
You will need a fairly beefy PSU to deal with the AMP Extreme Holo – total system power draw came in at over 660W in my testing. Zotac recommends an 800W PSU which would be fine, but if you're planning a new build around one of these cards, I'd feel more comfortable with a 1000W unit, both to give more efficiency headroom now, but also to ensure there's ample wattage left over for future upgrades.
We also 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. This provides us with significantly more accurate data to work with as it is measuring only the GPU power, and not total system power which is a fundamentally imprecise measurement.
This last graph illustrates just how much extra power the AMP Extreme Holo draws compared to the other RTX 3090 models we have tested. Both BIOS, by the way, share the same power target – the only difference is fan speed.