We take our noise measurements with the sound meter positioned 1 foot from the graphics card.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 the 3DMark Fire Strike Ultra stress test 20 times.
PowerColor wins here, thanks to its low fan speed of 1,100rpm. Sapphire uses 1,370rpm in Silent mode and 1,500rpm in Performance mode with the result that noise levels are slightly higher.