Cooling Efficiency Tests
First, let’s see what the coolers can do without any fans.
For our comparative test to be correct, we lowered the speed of the system fans to 600 RPM so that they didn’t help the coolers much. The side panel of the system case was open, which worsened the airflows inside the chassis and made it harder for the coolers. There is one change in our test methods: the amount of memory for the Linpack x64 test was increased to 4750 megabytes (almost all of the free system memory). This makes the test longer, which is important for passive heatsinks.
First, let’s see how the coolers cope with a non-overclocked six-core CPU (these are the results of the second test cycles):
It is clear that we have no winner at the default CPU frequency. The coolers produce identical results. Next, we overclocked our CPU to 3.8 GHz and tested the coolers once again.
Surprisingly enough, we’ve got identical results again! Both coolers make the CPU stable at a clock rate of 3.8 GHz. This is good already but can we overclock our six-core CPU even more with these passive heatsinks? Yes, we can!
We’ve got impressive results indeed. Even some coolers with fans fail to reach a CPU frequency of 4.1 GHz and we achieve it with passive heatsinks! The new model from Thermalright is 1°C better than its opponent at peak load. Moreover, that frequency was the maximum we could achieve with the Noctua whereas the Thermalright HR-02 could perform one more feat (the amount of memory allocated to the test program was increased a little more):
Now let’s put all the results into a single diagram:
The Noctua NH-D14 loses its title of the best cooler for fan-less mode even though it is but slightly inferior to the Thermalright HR-02.
Now let’s see what our coolers can do if they are equipped with fans. The Noctua NH-D14 was installed as in the photo from the Testbed and Methods section of the review. The Thermalright HR-02 was installed in the proper way so that its airflow was directed towards the back panel along the heatsink. For the back-panel 120mm system fan not to intervene with the competition, we removed it. This also made it simpler for us to install a second exhaust fan on the HR-02. You can see the results of our test in this table and in the following diagram:
Thermalright engineers were right to claim that the HR-02 is invincible with one fan. This cooler beats the Noctua NH-D14! And the lower the speed of the 140mm fan, the larger the advantage of the HR-02 is. The Noctua NH-D14 is better with two fans, though.
When equipped with two fans, the coolers are equal at 610 RPM, but the Noctua goes ahead at higher speeds, winning by 1-2°C and remaining the best cooler in active mode with two fans.
And finally, let’s check out both coolers with the CPU overclocked to 4.46 GHz at a voltage of 1.4625 V. We ran this test with two fans at 810 and 1240 RPM.
Although the room temperature remained rather high during this test (about 28°C), both coolers coped with their job and made the well-overclocked Intel processor perfectly stable. The Noctua NH-D14 wins here, outperforming its opponent by 3°C in quiet mode and by 1°C at the maximum speed of the two 140mm Thermalright TY-140 fans.