Cooling System: Efficiency and Noise Level
Two rubber pipes (about 400 mm long and 10 mm in diameter) are press-fitted onto the radiator’s nozzles.
The radiator is 38 mm thick, which is about twice as thick as Asetek's cheapest and thinnest models, so we guess that installing a second fan on it might help drop the temperature down by a few degrees more and lower the noise level along the way.
There’s a pump mounted on each GPU, featuring a copper waterblock with microchannel design.
The pumps are connected sequentially, so one GPU is going to be somewhat hotter than another. We don’t know the specified output power of the pumps but they are absolutely silent at work. There are round depressions in the bases of the waterblocks for GPU dies.
The face-side memory chips are cooled by a steel plate with low-profile finning. There’s a copper heatsink on the power transistors.
Like the PCB itself, it is cooled by the central fan.
The fan is 85 mm in diameter. Its speed is PWM-regulated but we couldn’t monitor it using our software tools.
The fan has four LEDs and is highlighted in red.
The word “RADEON” on the cooler casing should be highlighted as well, but this highlighting didn’t work on our sample of the card.
To measure the temperature of our Radeon R9 295X2 we ran Aliens vs. Predator (2010) five times at the maximum visual quality settings, at a resolution of 2560x1440 pixels, with 16x anisotropic filtering and with 4x MSAA.
We used MSI Afterburner 3.0.0 beta 19 and GPU-Z version 0.7.8 to monitor temperatures and other parameters. We didn’t install the graphics card’s radiator inside our computer case because we would have had to use one more 120mm fan and thus help the cooler with its work. Of course, the open computer case aids the cooler too, but not as much as two fans installed on the radiator would have helped.
We can add that the room temperature was 25°C during our tests. Let’s see how efficient the cooler is with its fans regulated automatically.
As you can see, the liquid cooling system copes well with its job, keeping one GPU as cold as 63°C. Unfortunately, the temperature of the other GPU is not monitored, yet even if it's higher by 5°C, the result is just excellent for a graphics card with a heat dissipation of 500 watts.
We can remind you that reference Radeon R9 290X and 290 cards quickly reach a GPU temperature of 94-95°C and then have to drop their GPU clock rate, provoking a performance hit. Even though the liquid cooling system is a forced solution, it does work well here, also in terms of the noise level. The fan on the radiator is inaudible even when you install the latter outside your computer case. And the fan on the graphics card itself only gets noisy under continuous 3D load. The AMD Radeon R9 295X2 is not quiet, yet it seems to be subjectively much quieter than the reference Radeon R9 290X/290 or GeForce GTX 780/780 Ti.
Practice suggests that dual-processor graphics cards generally have low overclocking potential. Today we've got a leading solution of this kind with a power draw of 500 watts but the high-performance liquid cooling system does give us some hope for good overclocking. Indeed, we managed to speed up the GPUs by 67 MHz (+6.6%) and the graphics memory by 760 MHz (+13.2%).
The resulting clock rates were 1085/5760 MHz.
The liquid cooling system coped with the overclocked Radeon R9 295X2 easily. The peak GPU temperature was only 65°C, so we didn't have to worry about GPU throttling.
We guess the liquid cooling system is a clever and adequate solution, even though it makes you look for a place for its 120mm radiator inside your computer case. And you can increase its efficiency even more by mounting not one but two fans on the radiator!