How we were testing
We already know that the biggest weakness of the cooler are fans. So, we replaced them with reference models and observed the difference. This led to a remarkable comparison of Okeanos and Noctua NH-D15 heatsinks. And there are few surprises even in modes without the same fans. Let’s take a look at how Okreanos manages to cool the area around the socket, and what it really can do in passive mode.
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 a 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. We replaced the reference fans with the number corresponding to the original set. Usually one or two. For a better orientation, it is marked in the charts (1/2 ×).
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.
We already know that the biggest weakness of the cooler are fans. So, we replaced them with reference models and observed the difference. This led to a remarkable comparison of Okeanos and Noctua NH-D15 heatsinks. And there are few surprises even in modes without the same fans. Let’s take a look at how Okreanos manages to cool the area around the socket, and what it really can do in passive mode.
Cooling the MOSFETs
| Cooler | Speed and voltage of the fan | ||||
| 39 dBA | 33 dBA | ||||
| Arctic Freezer 33 | 1× 1148 rpm | 8.8 V | 1× 848 rpm | 6.23 V | |
| SilentiumPC Fera 3 v2 | 1× 1393 rpm | 9.4 V | 1× 971 rpm | 6.59 V | |
| Noctua NH-D15 | 2× 1073 rpm | 8.1 V | 2× 700 rpm | 5.87 V | |
| Reeven Okeanos | 2× (1044 + ? rpm) | 7.77 V | 2× (800 + ? rpm) | 7.58 V |
We already know that the biggest weakness of the cooler are fans. So, we replaced them with reference models and observed the difference. This led to a remarkable comparison of Okeanos and Noctua NH-D15 heatsinks. And there are few surprises even in modes without the same fans. Let’s take a look at how Okreanos manages to cool the area around the socket, and what it really can do in passive mode.
With the same fans
We already know that the biggest weakness of the cooler are fans. So, we replaced them with reference models and observed the difference. This led to a remarkable comparison of Okeanos and Noctua NH-D15 heatsinks. And there are few surprises even in modes without the same fans. Let’s take a look at how Okreanos manages to cool the area around the socket, and what it really can do in passive mode.
Passive mode (+ prints of the compound)
Prints after the disassembly
We already know that the biggest weakness of the cooler are fans. So, we replaced them with reference models and observed the difference. This led to a remarkable comparison of Okeanos and Noctua NH-D15 heatsinks. And there are few surprises even in modes without the same fans. Let’s take a look at how Okreanos manages to cool the area around the socket, and what it really can do in passive mode.
Conclusion
When it comes to cooling of VRM, Okeanos does not stand out much. The results are not exactly bad, but it is simply not the strong side of this cooler. Slightly higher temperatures (even when compared to the Fera 3 v2 with one fan) can be explained by the fact that the ribs are quite long, and even a 140mm fan cannot exceed. It means that the airflow is concentrated on the heatsink only.
A pleasant surprise was passive mode. Without fans, it is even better than NH-D15. Two narrow towers obviously work very well for system fans. However, the efficiency (power/weight) is still a bit worse than with the Zalman FX70. But it does not matter, Okeanos is a versatile cooler that can basically handle any situation.
With reference iPPC F12 and with very high flow rate, Okeanos is not as good as Noctua. But that was expected. D15 weights 200 g more. With reduced flow, the difference in efficiency shrinks and, at very low noise levels, Okeanos even leads at times. Tighter ribs can exploit weaker airflow more effectively. If you need really quiet cooler, go for Okeanos heatsink. If you need high cooling performance, go for NH-D15.
The efficiency (performance/noise) is decent. The optimization of Cold Wing 14 rotor is considerably better than the optimization of NF-F12 for the Okeanos heatsink. The blades of the original fan are bigger, they nicely copy the whole surface of the heatsink, and there are more of them (two more). Therefore, if you decide to replace the original fans, use only 140mm models.
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