Cooling System: Efficiency and Noise
The ZOTAC GeForce GTX 780 Ti AMP! Edition is equipped with a top-class Triple Silencer cooler. It is a large and heavy design consisting of a main aluminum heatsink, additional heatsinks for the power system and memory chips, three fans, and a decorative metallic casing.
The cooler’s takes heat off the GPU and spreads it through five 6mm heat pipes that stick out of its copper base.
The pipes distribute the heat more or less uniformly within the two comparably sized heatsinks. For better heat transfer, the pipes are soldered to the heatsinks.
The whole arrangement is cooled by three fans from the China-based Apistek. The outermost ones are 74 mm in diameter (the GA81S2U model) whereas the middle one is 86 mm (the GA91S2H model).
The middle fan is PWM-regulated and used for speed monitoring. The two outermost fans seem to be regulated through voltage all together with the middle fan. The regulation range is 1000 to 3300 RPM.
The memory chips are cooled by an aluminum plate with thermal pads. There is an aluminum heatsink, about 6 mm in height, installed on the power system components.
To measure the temperature of the ZOTAC GeForce GTX 780 Ti AMP! Edition 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 17 and GPU-Z version 0.7.5 to monitor temperatures inside the closed computer case. The computer’s configuration is detailed in the following section of our review. All tests were performed at about 25°C room temperature.
In the automatic fan regulation mode the GPU of the reference GeForce GTX 780 Ti would get as hot as 86°C with the radial fan rotating at 3100 RPM. The Zotac’s GPU, although clocked 130 MHz higher, is only 70°C hot while its fans rotate at only 2160 RPM.
We guess that’s just a perfect result for such a fast single-GPU graphics card and it justifies the higher price of the original version from Zotac. You can also set the fans at their maximum speed and drop the peak GPU temperature down by almost 10°C:
Of course, the ZOTAC GeForce GTX 780 Ti AMP! Edition is going to be rather noisy in this case. Let’s check out how noisy, exactly.
We measured the level of noise using an electronic noise-level meter CENTER-321 in a closed and quiet 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.
In this test we’ll compare the Zotac GeForce GTX 780 Ti AMP! Edition with the reference Nvidia GeForce GTX 780 Ti and AMD Radeon R9 290X, as well as with the original EVGA GeForce GTX 780 Superclocked which features the ACX cooler. The vertical dotted lines mark the top speed of the fans in the automatic regulation mode. Here are the results:
Despite the fact that the Zotac GeForce GTX 780 Ti AMP! Edition is the quietest card in this test and even beats the EVGA GeForce GTX 780 Superclocked ACX in this respect, we cannot call it really quiet. It is audible against the background noise of a working computer in 3D applications. While not really comfortable in terms of noisiness, the new card is an obvious improvement on the reference GeForce GTX 780 Ti.
By the way, if you think that graphics cards of this class have such a high level of heat dissipation that they cannot be quiet at all, we will prove the contrary in an upcoming review of another original GTX 780 Ti.
As for the Zotac Triple Silencer, its fans and heatsink plates do not rattle or anything. The cooler is overall a well-designed and high-quality thing.
Our Zotac GeForce GTX 780 Ti AMP! Edition turned out to be excellent in terms of GPU overclocking but its memory wasn’t that good. We managed to increase its GPU and memory clock rates by 155 and 490 MHz, respectively.
The resulting GPU clock rates were 1161/1227 MHz (+15.4%) whereas the graphics memory worked at 7692 MHz (+6.8%):
Moreover, the GPU frequency would peak up to 1255 MHz in 3D applications, which is an excellent result for a top-end Kepler-based GPU. This achievement is even more impressive considering the temperature factor:
When overclocked, the Zotac gets a mere 1°C hotter (71°C) and the top speed of its fans is only 70 RPM higher. So, the pre-overclocked GeForce GTX 780 Ti AMP! Edition can be overclocked even further, at least in terms of GPU frequency. Just a perfect result!