Cooling System: Performance and Noise Level
You may be already familiar with the ASUS DirectCU II cooler from our earlier reviews. It is installed on graphics cards of different levels, not only top-end ones, by the way. The ASUS ROG Matrix 7970 features one of its versions with five heat pipes, three of which are 8 mm in diameter and two are 6 mm in diameter. The aluminum heatsink consists of two sections and is covered with a metallic casing with fans.
The fans are 100 mm in diameter and support PWM-based regulation. Taking the cooler apart further would spoil the casing (we’d have had to unglue the decorative inserts in it), so we only show you a photo of the contact spot of the cooler's copper base:
To test the cooler efficiency we are going to use five consecutive runs of a pretty resource-consuming Aliens vs. Predator (2010) game with the highest image quality settings in 2560x1440 resolution with 16x anisotropic filtering and MSAA 4x antialiasing. We used MSI Afterburner 3.0.0 beta 9 and GPU-Z version 0.7.0-0.7.1 for monitoring of temperatures and other parameters. All tests were performed inside a closed system case at 25°C room temperature.
Let’s see how efficient the DirectCU II is on the ASUS ROG Matrix 7970:
AUtomatic fan mode
Maximum fan rotation speed
With the fans regulated automatically, the GPU was only 70°C hot and the peak speed of the fans was 1900 RPM. Considering the increased GPU frequency, the result is just excellent. At the maximum speed of the fans (3200 RPM), the GPU was a mere 4°C colder, so there is no point in accelerating the fans.
The ASUS ROG Matrix 7970 has a handy Matrix LED Load Indicator in its top part:
Depending on GPU load, this indicator changes its color into one of five variants:
So you can easily monitor your graphics load in a visual way. The indicator looks quite attractive, too.
The noise level of each cooler was measured between 1:00 and 3:00 AM in a closed room about 20 m2 big using CENTER-321 electronic noise meter. The noise level for each cooler was tested outside the system case when the only noise sources in the lab were the cooler and its fan. The noise meter was installed on a tripod and was always at a 150 mm distance from the cooler fan rotor. The tested cooling systems were placed at the edge of the desk on a sheet of polyurethane foam. The lowest noise reading our noise meter device can register is 29.8 dBA and the subjectively comfortable noise level in these testing conditions was around 36 dBA (do not mix it up with low noise level). The fan(s) rotation speed was adjusted in the entire supported range using our in-house controller by changing the voltage with 0.5 V increment.
To estimate the level of noise generated by the ASUS ROG MATRIX 7970 cooler we also included the acoustic measurements HIS 7970 IceQ X² GHz Edition, ASUS GeForce GTX 680 DirectCU II TOP and reference AMD Radeon HD 7970 GHz Edition graphics card. Let’s see what we ended up with:
Unfortunately, the ASUS ROG Matrix 7970 isn’t as good in terms of noise level as in terms of temperature. In fact, the ASUS is no quieter than the reference AMD Radeon HD 7970 GHz Edition, which is considered very noisy. It is also odd that it is inferior to the ASUS GeForce GTX 680 DirectCU II TOP that uses almost the same cooling system. It is only thanks to lower fan speed that the ASUS ROG Matrix 7970 is quieter than the AMD Radeon HD 7970 GHz Edition. And it only remains quiet or comfortable in 2D applications.