All the reviews I have seen on these 2 cards indicate that the Sapphire card is actually quite loud and is significantly louder than the Gigabyte. The ASUS CUII Top is the quietest R9 280X by far. Also, dB math is important to understand for noise level. A simple (or as some say small 3dB) difference is actually twice the noise level. Every 3dB increase doubles the noise.