We take our noise measurements with the sound meter positioned 1 foot from the graphics card. I measured the noise floor to be 32 dBA, thus anything above this level can be attributed to the graphics cards. The power supply is passive for the entire power output range we tested all graphics cards in, while all CPU and system fans were disabled. A reading under load comes from running A Plague Tale: Requiem for 30 minutes.
Noise levels of the ASUS Prime are absolutely fantastic, it has to be said. The Quiet BIOS saw the fans run at below 800rpm, not even registering on my sound meter. The Performance BIOS only increased speed to 1350rpm, so it was still very easy on the ears.