Passive cooling
Cooling the processor is one thing, but cooling its power supply circuit is another. How will the coolers handle this task? We specially focused on testing the heatsinks with Noctua reference fans. Notably, the weird Freezer had some real difficulties. We know where the problem is. We made some tests without fans too, and on this occasion we decided to include top-notch passive cooler Zalman FX70.
Bonus tests of coolers are a regular extension of standard reviews. In addition to cooling efficiency around the socket, they include testing and comparison of heatsinks using the same fans as well as fully passive operation without any active cooling. And also other various tests that might be interesting for the particular cooler.
How we were testing
During the tests, we also measured CPU MOSFETs heating at 33 and 39 dBA. We put the sensor right into the heatsink. These tests always begin with the same starting temperature (35 °C). Although Gigabyte is known for an excellent cooling of its power supply and manages to maintain very attractive temperatures, it is still easy to determine which of the coolers more or less keeps doing a good job cooling the critical components.
The fans were aligned in such a way that they do not exceed over the top rib because it would be pointless there. It is more important to swirl the air in the lower parts. This was still measured with the default fans.
In the next phase of the tests, the original fans were replaced by the reference fans to create the performance comparison of the heatsinks with the same fans. These results might come in handy when you want to replace the default fans. Usually because they are too fast or too slow (and inefficient), or they produce disturbing sounds, or for whatever reason based on personal preferences.
Optimal candidates for such tests are the “industrial” Noctua NF-F12 iPPC fans. Thanks to their wide range, we could test with a very high flow and at a very low noise level. We increased the flow of the system fans (4× 1200 rpm) only in 24 V mode (2000 rpm without any problems). For a better comparison, we also included the tests with standard 4× 550 rpm. After reducing the voltage to 15 V, the fans were relatively quiet (1290 rpm) and at 9 volts they were running at 765 rpm only, which could be especially challenging for large two-tower heatsinks and larger liquid coolers.
Finally, the coolers competed with each other without a fan. The processor we used was Core i7-5930K (TDP 140 W) with Vcore 0.9 V, which had 25 W lower power consumption than with default settings. These tests took longer than those before, 900 seconds. Most coolers cannot handle this. After 95 ºC, tests were interrupted and considered unsuccessful. Therefore, temperatures in idle are also interesting. We used traditional configuration of system cooling and airflow. To have something to reflect to, we tested Zalman FX70 first. It is not produced anymore, but it is still one of the best coolers that Zalman has ever made, and it rarely finds a worthy opponent.
Cooling the processor is one thing, but cooling its power supply circuit is another. How will the coolers handle this task? We specially focused on testing the heatsinks with Noctua reference fans. Notably, the weird Freezer had some real difficulties. We know where the problem is. We made some tests without fans too, and on this occasion we decided to include top-notch passive cooler Zalman FX70.
Cooling the MOSFETs
| Cooler | Speed and voltage of the fan | ||||
| 39 dBA | 31 dBA | 33 dBA | 31 dBA | ||
| Arctic Freezer 33 | Arctic Freezer 33 | 1148 rpm | 8.8 V | 848 rpm | 6.23 V |
| SilentiumPC Fera 3 v2 | SilentiumPC Fera 3 v2 | 1393 rpm | 9.4 V | 971 rpm | 6.59 V |
Cooling the processor is one thing, but cooling its power supply circuit is another. How will the coolers handle this task? We specially focused on testing the heatsinks with Noctua reference fans. Notably, the weird Freezer had some real difficulties. We know where the problem is. We made some tests without fans too, and on this occasion we decided to include top-notch passive cooler Zalman FX70.
With the same fans
Cooling the processor is one thing, but cooling its power supply circuit is another. How will the coolers handle this task? We specially focused on testing the heatsinks with Noctua reference fans. Notably, the weird Freezer had some real difficulties. We know where the problem is. We made some tests without fans too, and on this occasion we decided to include top-notch passive cooler Zalman FX70.
Passive cooling
Cooling the processor is one thing, but cooling its power supply circuit is another. How will the coolers handle this task? We specially focused on testing the heatsinks with Noctua reference fans. Notably, the weird Freezer had some real difficulties. We know where the problem is. We made some tests without fans too, and on this occasion we decided to include top-notch passive cooler Zalman FX70.
Conclusion
With Freezer 3, there was a slightly more intense heat around the socket. At 36 dBA, the heatsink of the MOSFETs was warmer by more than 4 °C. The fan is partially to blame because it does not exceed over the bottom rib that much, but what plays a big role especially is significantly more intensive heating of the base. While Fera, regardless of the orientation of the motherboard, reached 39 °C at most, the base of the Freezer stayed below 40 °C only in the horizontal position. In the vertical position, temperatures climbed up to 54 ºC, which indicates a limited heat exchange between the pipes and the ribs.
Although the fan cooled the radiator as it should, the limiter is the structure of the “slow” pipes. This problem was confirmed by the test of the heatsinks without a fan, in which Freezer (even with the motherboard vertically) was better than Fera. That is because this time the least effective part was radiator itself. It is not suitable for passive cooling in any case. None of the coolers managed to handle the burn as expected (it was over after approximately four minutes) and Zalman FX70 remains unreachable even in the idle mode with low consumption chip. The ribs are just too tight to be taken care of by a breeze of the system cooling.
On the other side, wide gaps between the ribs of FX70 are not very practical for the active cooling with extreme flow. However, Fera 3 pushes its limits in this domain. Compared to the default fan, it can be improved by 2 °C, but this small increase in cooling performance is not adequate to noise increase which was enormous. But it might be acceptable for users that are trying to reach the limits with an inexpensive air cooler. Settings below 40 dBA are more interesting in common practice. We have to admit that SilentiumPC has optimized the shape of the fan for the heatsink very well. At 39 dBA, the cooler did not achieve better results even with the Noctua NF-F12 fan. But that does not change the fact that the original fan has a broken sound which can be characterized by an unpleasant buzzing.
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