We have built a system inside a Lian Li chassis with no case fans and have used a fanless cooler on our CPU. The motherboard is also passively cooled. This gives us a build with almost completely passive cooling and it means we can measure noise of just the graphics card inside the system when we run looped 3dMark tests.
We measure from a distance of around 1 meter from the closed chassis and 4 foot from the ground to mirror a real world situation. Ambient noise in the room measures close to the limits of our sound meter at 28dBa.
Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on only the video card. It also brings us slightly closer to industry standards, such as DIN 45635.
KitGuru noise guide
10dBA - Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA - High Quality Computer fan
40dBA - A Bubbling Brook, or a Refrigerator
50dBA - Normal Conversation
60dBA - Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA - City Traffic or a Garbage Disposal
90dBA - Motorcycle or Lawnmower
100dBA – MP3 player at maximum output
110dBA - Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum
The Direct CU II cooler is fantastic. The dual fans only spin at 1,100rpm when idle and this rises to 1,700 rpm under gaming load and 1,900 rpm under synthetic Furmark load. It is significantly quieter than the single fan reference cooler.