These sound results are not overly precise as I work in an area with high ambient noise levels. As such, don’t take these results as gospel truth, but more as a general indication of overall noise levels.
We take our measurements with the decibel meter on the top and middle section of the case, overhanging the side panel (power supply side, not motherboard tray side) by exactly 1 inch to avoid any airflow pressure coming from the exhausting AIO cooler.
I measured the sound floor to be 38 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 and all CPU and system fans have a fixed fan speed (25%) completely isolating them from any changes in temperature across the system.
Noise levels were measured after 5 minutes of load under three scenario: Furmark, Fire Strike and desktop idle in sequential order with 2 minutes downtime in between each test.
The Sapphire Pulse cards are some of the quietest I’ve tested, with the aftermarket cooler putting the reference RX 480 design to shame.
The card also idles completely silently thanks to its passive fan mode.