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Cooling System: Efficiency and Noise Level

The AMD Radeon R9 290X is equipped with a cooler whose design hasn't changed much since AMD’s earlier reference coolers. The plastic casing fastened with several screws around the base frame covers a large aluminum heatsink, a steel heat-spreading plate and a radial fan:

The heatsink is soldered to the base which has contact with the memory chips and power components via thermal pads.

The heatsink consists of slim aluminum fins soldered to a copper base:

The base is a large vapor chamber with too much of thick and viscous thermal grease in the middle.

The fan drives the air through the heatsink and exhausts it out of the computer case. The 70mm blower is made by FirstD (the FD7525U12D model).

Its speed is PWM-regulated in a range of 1000 to 5500 RPM. The fan has a peak output power of 20.4 watts at 1.7 amperes.

To measure the temperature of the graphics card we ran Aliens vs. Predator (2010) five times at the maximum visual quality settings, at a resolution of 2560x1440 pixels, with 16x anisotropic filtering and with 4x MSAA.

We used MSI Afterburner 3.0.0 beta 17 and GPU-Z version 0.7.4 to monitor temperatures inside the closed computer case. The computer’s configuration is detailed in the following section of our review. All tests were performed at 25°C room temperature.

As we noted above, the reference Radeon R9 290X has two BIOS versions with different fan settings. There are two modes: Silent and Normal (or Quiet and Uber). They differ in how the fan's speed depends on the GPU's temperature and clock rate. Here's what we have in the Silent mode during the looped Aliens vs. Predator test:


Auto mode

At the beginning of the second test cycle the GPU grew as hot as 94°C, triggering thermal throttling (similar to what was first implemented in Intel CPUs a few years ago). The clock rate was lowered whereas the speed of the fan didn't exceed 2300 RPM (44% of the fan's full power). Although the noise level is out of the comfort zone, AMD calls this mode quiet. Of course, the card's performance is lower in this mode since the clock rate can drop down to 700 MHz, which is about 30% lower than the GPU's default frequency. Thus, the reference design doesn't seem to be attractive for practical purposes.

But the main problem is that when you switch to another BIOS and enable the Normal mode, the fan can accelerate up to 49% or 2800 RPM, which is still not enough to avoid the frequency drop. The GPU gets 94°C hot again, just not so quickly – during the fourth test cycle. That’s why we tried to find out the fan’s speed which would prevent the GPU from slowing down. We almost did it at 55% and 3020 RPM, yet the frequency would still sag down to 978 MHz occasionally:


55 % fan speed

So we sped the fan up to 60% or 3340 RPM:


60 % fan speed

The GPU was no hotter than 87°C then and didn’t suffer any frequency drops. The card was too noisy at that speed of the fan, of course.

After we took the card apart and replaced its default thermal grease with Arctic MX-4, we carried out our temperature test one again and saw that there were no frequency drops at 55% fan speed.


55 % fan speed + Arctic MX-4

Replacing the default thermal interface seems to do the card some good. The peak temperature was close to the threshold, though. It is quite possible that the frequency would have dropped if the test had lasted longer.

We measured the level of noise using an electronic noise-level meter CENTER-321 in a closed and quiet room about 20 sq. meters large. The noise-level meter was set on a tripod at a distance of 15 centimeters from the graphics card which was installed on an open testbed. The mainboard with the graphics card was placed at an edge of a desk on a foam-rubber tray. The bottom limit of our noise-level meter is 29.8 dBA whereas the subjectively comfortable (not low, but comfortable) level of noise when measured from that distance is about 36 dBA. The speed of the graphics card’s fans was being adjusted by means of a controller that changed the supply voltage in steps of 0.5 V.

We’ve included the results of the reference Nvidia GeForce GTX 780 and two original cards, EVGA GeForce GTX 780 Superclocked ACX and MSI Radeon R9 280X Gaming, in the diagram below for the sake of comparison. We’ll also use these cards in our performance tests. The vertical dotted lines mark the top speed of the fans in the automatic regulation mode. There are two such lines for the AMD Radeon R9 290X: for the automatic Silent mode and for 55% fan speed.

Here are the results:

The Radeon R9 290X is the noisiest reference card. We had expected that even before the test, judging by our subjective impressions. The high heat dissipation of AMD's new flagship means that its noise in the quiet mode is about as high as with the reference GeForce GTX 780 but the latter doesn’t drop its GPU frequency by 30%. When running 3D games at a stable 1000 MHz, the Radeon R9 290X has 55% fan speed, which is unbearably noisy. This graphics card is just not meant for home users.

 
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