Thermal and Acoustic Performance

First, let’s take a look at the temperature of the overclocked quad-core CPU.

The results of the Auras SLC-747 and LPT-700 are quite what you could expect from them. The Auras LPT-709 is a nice surprise as it features high cooling performance and is but slightly inferior to the Zalman CNPS9700 LED, which is about $30 more expensive, in the system case. The Auras CTC-868 is a rather mediocre cooler as it is not only worse than the junior LPT-709 but also than the twice cheaper Cooler Master Hyper TX.

Note that the CTC-868 improves its performance by about 5°C on the open testbed when its fan speed is increased. When tested in the unfolded form, the peak temperature was 3-4°C higher, which agrees with my supposition that it was the middle, stationary, part of the cooler, rather than the unfolding sides that had the maximum thermal load. I didn’t include the results of the CTC-868 with an unfolded heatsink into the diagram above due to their uselessness.

The table below shows the temperature data of the other CPU and mainboard sensors (Core 0 and 1, 2 and 3 results were identical, so there are only Core 0 and 2 data here).

I also found out the maximum CPU frequency I could achieve with each cooler. Here are the results:

The CPU voltage data didn’t fit into the diagram. The voltage was set differently in the maximum frequency test:

• Auras SLC-747 ~1670rpm | ~2600rpm: 1.4750V | 1.4875V
• Auras LPT-700 ~1680rpm | ~2370rpm: 1.4750V | 1.5000V
• Auras LPT-709 ~1680rpm | ~2620rpm: 1.5750V | 1.5875V
• Cooler Master Hyper TX ~1470rpm | ~1890rpm: 1.5750V | 1.6000V
• Auras CTC-868 2 x 1790xrpm | 2 x 2420rpm: 1.5375V | 1.5625V
• Zalman CNPS9700 LED ~1670rpm | ~2820rpm: 1.5875V | 1.6250V

The Auras LPT-709 goes on giving out good results, even though it is somewhat inferior to the cheaper Hyper TX on an open testbed. The CTC-868 is somewhat better now, yet its price still seems to be too high for its performance. The Zalman CNPS9700 LED is beyond competition in both quiet and max speed modes just as a cooler of its class should be. I don’t think the coolers tested in this review should be compared with those we tested earlier because the testbed now uses a different mainboard that allows to reveal the full potential of a CPU with air cooling. For example, the Thermalright Ultra-120 eXtreme with two 120mm fans keeps the quad-core CPU stable at 3.55GHz with a voltage of 1.65V.

The next diagram shows the noise level of each cooler measured according to our traditional methodology described in the previous articles (the subjectively comfortable level of 36dBA is marked with a dash line; the ambient noise from the system case, without the CPU cooler, was about 34dBA):

There is nothing much to comment upon. Every cooler from Auras supports PWM regulation and can be made to work quietly. Their performance in the quiet mode and at the max speed has been shown above.