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Roundup: the Radeon HD 7970s and 7950s from Asus, HIS, MSI, PowerColor, Sapphire and XFX
by Damien Triolet
Published on May 9, 2012

Test protocol 2.0
After two and a half years of loyal service, we have decided to pension the Sonata 3 off as well as the first version of our full test protocol given over to measuring the thermal characteristics of graphics cards. Over the years we have looked in detail at no fewer than thirty-seven graphics solutions, thanks in particular to thermal imaging and this formed a useful database, giving us the ability to position the results of new solutions objectively.

Test protocol 2.0 has also been designed to be used for a while. Here we use a Cooler Master RC-690 II Advanced casing, which is radically different to the Sonata 3. With many perforations, it’s also better equipped cooler wise, with a 140 mm suction fan at the front and 120 mm and 140 mm extraction fans at the back in place of the single 120 mm fan on the Sonata 3.
We have also modified it slightly by replacing the original set of fans with Noctua models: an NF-P14FLX to suck air in and two NF-S12Bs for extraction. This modification improves the cooling to noise ratio and above all removes the mechanical noise you get with the original fans. Although this noise didn’t alter the noise pressure obtained during readings by much, it did make it difficult to register noise levels by ear, which is important when the graphics card fan is also producing a mechanical noise or when its speed varies.


Instead of the X48 and Q6600, we’re now on a P67 and Core i7-2600 platform. We went for the Asus Sabertooth P67 motherboard which has an additional slot between the CPU and the first graphics port, making it easier to take infrared photos. We did however remove its plastic protection which was stopping us from viewing the temperature of various areas of the PCB. While we previously used the Intel cooler box, here we went for a Big Shuriken from Scythe, which is more effective and isn’t subject to the size issues you get with tower models (again a problem when taking the photos).

We used a Scythe Kaze Master rheobus to control the speed of the CPU and case fans. The CPU fan was thus fixed at 900 RPM both at idle and in load. The Noctua fans run at 600 RPM in idle, while in load the 140 mm ups its speed to 780 RPM and the 120 mm to 990 RPM.

We opted for a high-end power supply: the Seasonic X850. It has the advantage of being passive when energy consumption is under 200W, namely when our system is at idle. We used an OCZ Vertex 2 64 GB for the system disk and two hard drives, a Hitachi Deskstar 7200 RPM and a Western Digital Raptor 10000RPM, as secondary drives.

Thanks go to Asus, Cooler Master, Intel and Seasonic for supplying most of the components required for setting this test system up.

We kept our Fluke Ti25 thermal camera for the readings, which gives us an image of the different temperatures that we also took using the sensors on the Asus Sabertooth. However we did replace our sonometers with the Cirrus Optimus CR152A Class 2 models that allow us to measure sound levels down to 21 dBA, which is as low as the room allows us to go. The noise level readings are not therefore comparable with the old ones, which went down to a minimum of 35 dBA.


The sonometer was mounted on a base and placed 50 cm from the side of the casing, raised up 20 cm from the table on which the casing was placed. The solutions measured at between 21 and 22 dBA can be considered as silent. Up to 25 dBA and the cooling is very discreet. Between 25 and 30 dBA can be seen as discreet. Between 30 and 35 dBA can be seen as standard and between 35 and 40 dBA is starting to get noisy. Anything higher than this is noisy and can become excessive for a computer, though of course, as with the other thresholds, this is subjective and depends on several factors such as the regularity of the noise and the environment.

This time we decided to measure the noise levels both during standard usage of the casing and with the graphics card isolated, turning the hard drives and CPU and casing fans off. This allowed us to differentiate between the least noisy cards in much more detail.

The load test has also moved on. We have replaced the 3DMark06/07 Pixel Shader test, in which fps values went much too high, with the first scene from 3DMark 11. We opted for this one because it doesn’t use tessellation, a rendering technique that could lead to a drop in energy consumption on cards that suffer from a bottleneck at this level. This scene is however 5% less demanding in terms of energy consumption than that in 3DMark06, which worked the texturing units a good deal more. This load test is therefore now very similar to a very demanding game and a good deal different to tests such as Furmark and OCCT in terms of energy consumption. The CPU was loaded with Prime95 on 4 threads, with the lowest priority.

Here’s how we organised the tests:

- Ambient temperature reading to keep it between 25 and 26°C
- 45 minutes at idle
- Noise level reading
- Temperature sensor readings
- Casing is opened rapidly for thermal imaging photo
- Casing is closed
- 45 minutes in load
- Noise level reading
- Casing is opened rapidly for thermal imaging photo
- Casing is closed
- Temperature sensor reading via log
- 45 minutes in load with overclocking
- Noise level reading
- Casing is opened rapidly for thermal imaging photo
- Casing is closed and two hard drives turned off
- GPU temperature sensor reading via log
- CPU and casing fans switched off
- Speed of GPU fan fixed manually to idle/load/overclocking/100% and noise reading taken.

Note that with these last readings we made sure the RPMs were identical and not only the speed expressed as a %, as they can vary slightly with the voltage supply to the fan when the GPU is in load.

Lastly, the readings taken during overclocking were taken pushing the card as far as it would go, including a modification of the GPU voltage as well as memory overclocking.

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