Noise level measurement
Bustin' out the sound meter in a room where the noise floor is 28dB, we've measured the idle, Black Ops, and FurMark load by placing a PCE-318 meter directly at the front of a Corsair 700D chassis. Bear in mind that the cards are screwed in and the side panel is on. The numbers reflect the average noise profile between minutes eight and 10 of the tests.
The test system's noise floor is around 34dB with a passive card. Any figure below 36dB can be considered practically silent, and all three Radeon HD 6850s do well here.
Play Call of Duty: Black Ops for 10 minutes and, much like the temperature and power tests, the differences are clearer. Bear in mind that decibel ratings are logarithmic in nature, meaning that an increase of three decibels indicates a doubling of the noise and a jump of 10dB is equivalent to a 10x sound increase.
The ASUS and PowerColor cards do very well here, being barely louder than at an idle state. In fact, it's very difficult to discern that they're spinning up at all. The Sapphire card, on the other hand, is significantly louder, coming in at 42dB. We ran the test several times and the results were consistent.
Give the GPUs some real beatings and any figure around 40dB is excellent for a mid-range card. Again, the ASUS and PowerColor HD 6850s do a good job of not annoying the ears, while the Sapphire TOXIC is almost twice as loud. It's hard to explain given how much attention has been paid to the cooling.
