We thought it’d be fun to revisit the leading large fan of its time, the SilverStone AP181, and test it for airflow, noise, and cooling performance versus the more modern Noctua 200mm & CM 200mm fans. Note that, as always with fans, the most important metrics are those of airflow (measured in linear feet per minute) and noise (dBA). Temperature testing has enough variables, as does fan testing, that it is difficult to establish differences outside of error. Note also that we’ve changed our testing approach from the previous 200mm content, with previous testing using a mesh modified H500P. Our new testing reverts to the stock H500P (acrylic front) to create greater impedance and a worst-case scenario. Our LPM + dBA testing remains the same, and we’re still using a Throne side panel for mesh impedance testing.

Case & Fan Testing Methodology

All case fans are manually configured to their maximum throughput using BIOS, then we configure to an RPM closer to 1050 for a universal "quiet" testing. If a fan controller is present, we opt-in and test on multiple settings. This forces testing of case fan performance in addition to the case's air channeling and airstream design. This also ensures minimal variance when testing, as automatically controlled fan speeds can reduce reliability of benchmarking. The CPU fan is set to 1100RPM (constant) for consistency, and the CPU is overclocked to 4.4GHz with a vCore of 1.272V (constant). C-States and power saving states are disabled.

The video card is configured to run at 55% fan speed at all times.

Prior to load testing, we collect idle temperature results for ten minutes to determine the unloaded cooling performance of a case's fans and air channels. Thermal benchmarking is conducted for 1400 seconds (23 minutes), a period we've determined sufficient for achieving equilibrium. The over-time data is aggregated and will occasionally be compiled into charts, if interesting or relevant. The equilibrium performance is averaged to create the below charts.

Load testing is conducted using Prime95 LFFTs and Kombustor “FurMark” stress testing simultaneously. Testing is completely automated using in-house scripting, and executes with perfect accuracy on every run.

We recently validated our test methodology using a thermal chamber, finding our approach to be nearly perfectly accurate. Learn more here.

SilverStone 180mm vs. 200mm Fan LPM Testing

For airflow testing, we used an anemometer to measure linear feet per minute airflow through a metal filter side panel. This test uses an old Rosewill Throne side panel to measure airflow through the mesh, helping provide a real-world scenario test with some impeding objects.

Because we pulled the SilverStone AP181 out of the Raven case, we only tested the fan at its preconfigured 100% setting – 1300RPM – and preconfigured 65-70% setting, or 800RPM. At 800RPM, which is the same as the Noctua and Cooler Master fans at max, we measured 420LPM airflow, versus, roughly the same measurement from Noctua. These measurements are within margin of error of one another, and can be thought of as functionally equal. The Cooler Master fan runs a bit further behind, measuring at 378LPM. This is just 70% of SilverStone’s fan speed, though, and equalizes all 3 units to 800RPM. At 100% speed, or 1300RPM, we measured 620LPM airflow through the panel – this is impressive, and further establishes SilverStone’s legacy as one of the only companies to make a big fan that worked well.

SilverStone AP181 Noise Levels

Noise levels are fairly straight forward: The SilverStone fan operates at 44.5dBA under its maximum RPM of 1300, with roughly a 34dBA at 800RPM. This matches it near the Noctua and Cooler Master fans at the same 800RPM – or 100% RPM, for those two. Although objectively louder at max RPM, the SilverStone fan can push better noise-normalized performance, and has more headroom for bursting fan speeds under heavier loads.

Thermal Testing – Best 200mm Fans

Again, note that this is the least important segment, given error margins. Also note that we retested with a different front panel than last time.

For thermals, our 3DMark CPU + GPU load testing puts us at 34 degrees Celsius dT over ambient for the Cooler Master stock fans, looking at CPU temperature. The Noctua fans established a 31.6C temperature, dropping about 2.5 degrees off of the stock Cooler Master fans. SilverStone’s AP181s, meanwhile, did about 28 degrees when maxed-out, or 31.4 degrees Celsius when matched to the same noise level as the Noctua and Cooler Master 200mm fans. This gives us a bit more headroom in terms of max performance, thanks to the 1300RPM peak RPM, but also means we can still noise normalize to match other fans, while retaining similar or equal performance.

We saw similar performance in a CPU Blender animation, where the SilverStone fan maintained a slight performance advantage over Noctua, which in turn retained a performance advantage over the stock Cooler Master fans. Of course, neither the Noctua nor SilverStone fan properly fit in the case, but the point is that these two units do overcome the static pressure impositions caused by the stock H500P.

Conclusion

SilverStone’s AP181 remains a performance leader in the realm of large fans. Now, to be fair, it isn’t actually compatible with the H500P – and neither is the Noctua fan, technically. For Noctua, only two screws fit, and the lower half is taped to the case (despite being 200mm). For SilverStone, we use one screw, then tape the rest of it to the case. In this way, it’s more an academic test than anything, as you wouldn’t really want to use the SilverStone fan in this capacity.

That academic test, however, does give us a good look at how the fans perform. If there’s an instance where the AP181 is compatible, it’s still a high-performing fan, and we still recommend it. SilverStone does have alternative and more modern versions, but we’ll look at those later.

Editorial, Testing: Steve Burke
Video: Andrew Coleman