Test results (dual-fan assemblies)
Now it's time to analyze performance of dual-fan assemblies - two twin configurations of Ultra-120 eXtreme (Noctua and Minebea fans) and one Ultima-90 assembly (with the reference Minebea fan).
Chart 11. Temperature readings (CPU core temperature, Noctua fans)
Chart 12. Noise characteristics (Noctua fans)
The situation here is expectedly similar to what we saw with dual-fan assemblies of the Noctua NH-U12P cooler. The most interesting modification is again the slowest pair (600 rpm) - the noise level does not grow much, but the assembly becomes much more efficient, which can help in PC cases with insufficient ventilation. However, similar performance results can be reached by raising rotational speed of a single-fan assembly, it will be less noisy. So in our opinion, dual-fan assemblies of Ultra-120 eXtreme with Noctua fans make no sense. But unlike Noctua NH-U12P, noise generated by these assemblies is quite ergonomic even at a relatively high speed (1300 rpm), no side tones.
The next dual-fan assembly of Ultra-120 eXtreme in our list is equipped with reference Minebea fans.
Chart 13. Temperature readings (CPU core temperature, Minebea fans)
Chart 14. Noise characteristics (Minebea fans)
This is generally a more illustrative situation. Cooling efficiency has apparently grown. However, some dual-fan configurations ruin the balance in noise terms - as we can see, the twin assembly (500 rpm) is outperformed by a single-fan configuration (700 rpm), generating the same level of noise. It seems that Thermalright engineers were right to disregard dual-fan assemblies of Ultra-120 eXtreme - they are not quite expedient. There is no need to use them, when a single fan is sufficient. Nevertheless, the intrigue with a twin Minebea assembly remains - temperature readings still go down at maximum fan speed (1900 rpm). That is, there is still a reserve left (which is probably enhanced by bent fins that shape the air flow). If you have no problems with noise, experiments with two high-speed fans (for example, Delta fans, 120x120x38 mm) may be very productive.
And in conclusion of this section we'll have a look at a dual-fan Ultima-90 assembly with reference Minebea 9cm High fans.
Chart 15. Temperature readings (CPU core temperature, Minebea 9cm fans)
Chart 16. Noise characteristics (Minebea 9cm fans)
It's a contradictory situation - efficiency grows together with noise. Nevertheless, taking into account that Ultima-90 is designed for compact PC cases (including fanless HTPC), slow fan couples may indeed improve performance of this cooler, raising its cooling capacity to the High-End level.
Conclusions
We don't see any rivals in thermal efficiency to Thermalright Ultra-120 eXtreme. Its assemblies with reference fans Scythe Minebea and Noctua NF-P12 demonstrate excellent efficiency practically in all speed modes, which noise does not exceed the ergonomic level. And they combine their efficiency with a record-breaking efficiency-noise ratio. Thermalright Ultima-90 also performs well. It demonstrates decent High-End results, even though it has a compact design. They have minor usability drawbacks, of course. But both products can be safely recommended to all enthusiasts, who want to minimize operating temperatures of their quad-core processors for Intel LGA775 and AMD Socket AM2 platforms.
Thermalright Ultra-120 eXtreme cooler gets our Original Design award for original engineering solutions in its heat sink.
We shall just wish Thermalright success and new achievements in the field of designing new premium-class coolers with proper bundles. And we shall keep tabs on the situation in the top sector of cooling systems.
