Performance Testing

Please refer to the dedicated test setup page as it applies to this review as well and I did not want to go over it separately to save on review space.


be quiet! sent over two units of the Silent Wings Pro 4 120 mm fan and I began testing by plotting the RPM response as a function of the PWM duty cycle for the three operating modes available here. Seen above is the average response for both fans and alongside is be quiet!'s own chart which ends up matching my findings well enough. I am happy to see a predominantly linear response in all three modes to allow for users to have the fans be extremely fast and loud or far more reasonable and actually quiet. There is a long PWM duty cycle response too, which is good to see, so custom fan curves can be easily set based on your CPU or GPU temperatures. Lastly, both fan samples tested near-identical to each other so this is also good news when it comes to sample variation, or lack thereof.


With the three operating modes charted, I decided to use the intermediate HS mode for further testing since it's already far beyond what most people looking at radiator fans would run their fans at. Seen above the the average RPM, once again, but also the measured volumetric airflow in CFM and fan noise in dBA at those data points. be quiet! rates the fan RPM to go up to 2500 RPM in this mode and I hit an average of 2543 RPM here at 100% PWM duty cycle going down to 643 RPM at 16%. The noise and airflow charts are also fairly linear, which is good to see, and I will mention there was zero bearing/motor noise in use too.


The charts above help put the Silent Wings Pro 4 in better context with the chosen RPM values reflecting usage scenarios most popular with watercooling even though some fans go higher as is the case here. The charts are to be considered for comparison within this result set only and are not to be compared with results from another test elsewhere owing to different testing conditions. Note that these are average values for all samples of each fan and do not reflect any sample variation, but the Silent Wings Pro 4 impresses in terms of continuing to be noise-optimized but besting the Silent Wings 3 in pure performance, in addition to several other contemporary fans sold today. There does appear to be a sweet spot at lower fan speeds and then again at higher fan speeds based on my results.


Instead of having CFM/dBA charts that can potentially be taken for more than they really offer, I am going back to my old roots and showing just three fans as a comparison—no more, no less. More would clutter up things I spent years trying to unsuccessfully solve with static images. Here I have the two best performers in my charts in the form of the excellent Noctua NF-A12x25 as well as the chart-topping Phanteks T30-120. Both of these are better pure performers and so those wanting the best cooling with their custom fan curves would fare better with either of those. Where the be quiet! Silent Wings Pro 4 comes back is by simply being quieter—partly as a result of not pushing as much air but also having a fan design that continues to take the company's name seriously. Given these fans also scale higher in fan speed, it's hard to go wrong with either of them. I will give the slight edge to be quiet! here for its clean aesthetics and customization for different use cases, as well as a standard 25 mm thickness that still manages to be competitive in performance.