Cooling System and Noise Level
The XFX R7970 Double Dissipation Edition is equipped with an original cooling system that combines two exclusive features: GHOST and Double Dissipation. The former helps the air flow cover as much of the card's PCB as possible and exhaust the hot air to the outside. The latter, mentioned in the card’s own name, works together with the former and refers to the two fans.
We must note, however, that the PCB actually gets very little of air flow because two thirds of the heatsink’s base are a vapor chamber and the remaining third is blocked by the curved-in ends of the aluminum fins.
Thus, the PCB and its power components are only cooled by the black metallic frame with thermal pads.
There is thermal grease between the GPU die and the cooler’s copper sole. The latter isn’t finished well, by the way.
The whole arrangement is cooled by two 9-blade 84mm fans which are PWM-regulated in a speed range of 1400 to 3600 RPM (according to monitoring tools).
We checked out the card’s temperature while running Aliens vs. Predator (2010) in five cycles at the highest settings (2560x1600, with 16x anisotropic filtering and 4x full-screen antialiasing). We used MSI Afterburner 2.2.0 Beta 11 and GPU-Z 0.5.8 as monitoring tools. This test was carried out with a closed system case at an ambient temperature of 25°C. We used Arctic MX-4 thermal interface for the card’s GPU.
Let’s see how efficient XFX’s original cooler is with its fans being regulated automatically and at their maximum speed:
Max rotation speed
When the fans are controlled automatically, the GPU has a peak temperature of 77°C. This is 8°C lower than the GPU temperature of a reference Radeon HD 7970 under the same conditions. That’s good. The result can even be called excellent considering that the fan speed is only 1900 RPM. The cooler is quite audible at that speed, yet the reference cooler is much louder at its 2650 RPM. At the maximum speed of the two fans the GPU temperature of the XFX R7970 Double Dissipation Edition lowers to 61°C, but that’s too noisy.
We measured the level of noise using an electronic noise-level meter CENTER-321 in a closed 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 Sapphire Radeon HD 6970 Dual Fan into the next diagram as that card features one of the quietest alternative coolers.
The noise graph of the XFX R7970 Double Dissipation Edition is close to that of the reference AMD Radeon HD 7970. However, the fans of the XFX card work at lower speeds under load, making it much quieter than the reference card. The Sapphire Radeon HD 6970 Dual Fan is in its turn quieter than the XFX R7970 Double Dissipation Edition throughout the entire speed range.