Results: Fan RPM And Noise
Fan Control and RPM
AMD is using a single high-RPM fan with nine thin rotor blades in the Radeon R9 Nano’s cooler. The blades are twisted toward the inside of the fan and turn at a maximum speed of 7000 RPM. For comparison, the Gigabyte GTX 970 Mini’s fan tops out at 3500 RPM. It has 11 rotor blades with a better geometric design. Consequently, it's less noisy.
We’ve added the temperature curve to the graph to make it easier to put these results into their proper context.
On average, the AMD cooler’s fan spins 500 RPM faster than Nvidia's. Then again, it also has to deal with 30W of additional waste heat.
Looking at the graphs, what jumps out immediately are the different shapes of the fan curves. AMD takes things slow, whereas Nvidia uses a more classic curve. AMD’s fan ramps up gradually until approximately 65 degrees Celsius. From there to approximately 72 degrees Celsius, it really gets going. We're reminded of prior implementations starting at 75 degrees Celsius.
Just like we did for the infrared measurements, we had to get creative in order to achieve good noise results. We recorded the fan speed, and then manually set the graphics card to this speed in our test room in order to measure the noise level of just the graphics card itself.
As usual, the fans are the worst offenders when it comes to noise. Unfortunately, the coils are doing their part as well, though. As long as the fan speed stays under 1500 RPM or so, AMD’s marketing slogan of “library” noise levels applies. It’s just too bad that there’s some very pronounced peaks to be seen on the spectrogram between 8 and 14kHz, which can't be ignored.
Once AMD’s graphics card hits 2600 RPM, the fan’s air turbulence and rotor noises drown out almost all of the coil whining.
From a distance of 50cm, we measured just under 46 dB(A) with our calibrated microphone. This is certainly well above what AMD would like you to believe according to its marketing materials, but it’s also a lot lower than some of the company's previous efforts. Remember uber mode?
Overall, this is certainly a respectable result. The way that the Radeon R9 Nano squeezes into our tiny case, 180W of waste heat can’t really be dealt with any better using air cooling. The Gigabyte GTX 970 Mini might operate at a somewhat lower noise level, 39.9 dB(A) and 42.3 dB(A) under full load, but the comparison isn't even close to fair given the performance discrepancy between them.
|Ambient Temperature22 °C||Open Measurementat Full Load(Fixed RPM)||Measurement ofComplete System at Maximum Load||Open Measurementat Idle(Graphics Card Only)|
|AMD Radeon R9 Nano||46.3 dB(A)||43.7 dB(A)||32.3 dB(A)|
|Gigabyte GTX 970 Mini||42.3 dB(A)||39.7 dB(A)||31.9 dB(A)|