The Test Platform And Methodology - Four Cores Under Load

We tested all of the coolers in this roundup on an Intel quad-core Core 2 Extreme QX6850 CPU. When all four cores are under full load, this model has a power consumption of 113.87 watts. In order to achieve this load, we use a multi-core version of Prime95 (ver.25.5a). The CPU displayed this power consumption when combined with the best water cooler we tested, reaching 62°C. The worse the cooler performs, the more energy the CPU will consume, as it will be operating at a higher core temperature. We decided to conduct the cooler tests on a quad-core processor with a high thermal dissipation, since many users overclock their processors, and coolers need to be able to satisfy these more sophisticated needs.

The cooler test setup.

The test platform with a water cooling solution installed.

The coolers were tested in a Gigabyte GA-G33-DS3R board with integrated graphics core mounted upright, the way it would be installed inside a tower case. Since most coolers these days utilize heatpipe systems to conduct heat away from the CPU, the position and orientation of the cooler can have a tremendous effect on its cooling performance, and by extension, its efficiency. Orientation may also impact the noise level of air-based cooling solutions. The temperatures of all four processor cores are measured directly at the digital temperature sensors (DTS). We calculate an average temperature and then create a line diagram from the data.

The duration of the measurement is determined by the maximum temperature that the cooler reaches. A very bad cooler may reach its highest temperature in a matter of seconds, while at the other extreme, a very efficient water cooler may take up to half an hour.

In this example diagram, the Zalman cooler has reached its final temperature of nearly 70°C after about 55 seconds.