Our acoustic measurements are less precise on this mid-range test system, the noise floor of the totally quiet testing room is 34 dBA as measured with a Benetech GM1351 Digital Sound Level Meter.
We take our measurements with the decibel meter on the top and middle section of the case, overhanging the side panel (PSU side, not Motherboard tray side) by exactly 1 inch to avoid any airflow pressure coming from the exhausting H100i V2.
The underlying noise level of the system, emitted by all the non-GPU hardware combined, is 35 dBa thus anything above this level can be attributed to the graphics cards. The PSU 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 completely isolating them from any changes in temperature across the system.
Noise levels were measured after 5 minutes of load under three scenario: Furmark, Unigine Heaven and desktop idle in sequential order with 2 minutes downtime in between each test.
Noise levels were impressive and align with other GTX 1080 Ti graphics cards using custom coolers. There is a sizeable reduction in noise compared to the Founders Edition card.
Fan speeds levelled out at around 1600 RPM (60% duty) under heavy extended loads which is audible but not significantly noticeable. At idle and low loads the fan stays off until it passes a threshold of 60 degrees Celsius.