Be quiet! Silent Loop 3 420 review: Performance cooling with minimal noise

Noise-normalized testing

Most testing is performed with the cooler tied to the default fan curve of my MSI X870E Carbon motherboard, but some of y’all prefer to see tests when the noise levels of coolers are equalized. This is especially important to those of you who prefer silent computers.

We’ll start with the “easiest” of these tests, which runs Cinebench R23 with a “stock” power limit. On our motherboard, this means the CPU will consume ~200W. The results are pretty much within expectations – outperforming all competing 360mm AIOs tested here, but falling a few watts behind Arctic’s Liquid Freezer III Pro 420.

The next test is a bit harder, with PBO enabled to allow the CPU to use as much power as it can handle – it handled an impressive 257W on average.

For the next test, we’ve added the heat of a GPU to the mix – which contributes 295W of thermals into the PC case. The results are similar to our other noise-normalized tests, and Be Quiet maintained its second-place position once again.

Noise levels

We’ve measured noise levels at two points to give you an idea of how the cooler operates when tied to a motherboard’s default fan curve. Our first measurement is when the fans are allowed to run at full speed, delivering the loudest noise levels possible.

In terms of maximum volume, Be Quiet’s Silent Loop 3 420 reaches 45.3 dBA – quieter than most AIOs that we’ve tested.

Our next acoustic measurement is the cooler’s volume when the CPU consumes 150W. This might be similar to your “worst case” gaming scenarios, especially if PBO is enabled. Noise levels are very good here, reaching only 37.3 dBA. This means the cooler runs virtually silent in most common workloads, and will only become audible in stressful scenarios.

PBO Performance – full fan speeds

While some of y’all prefer to run coolers at low noise levels, I know a lot of you just want maximum performance. This test lets the fans run at their full speeds, to test the full potential of the AIOs cooling capabilities. Turning on PBO allows AMD’s Ryzen 9 9950X to stretch its legs and guzzle power, pushing the limits of any CPU cooler on the market.

The Silent Loop 3 420 cooled more than 260W in this test, just a few watts behind the best results we’ve recorded – maintaining its overall second-place position.

200W thermal benchmarks and noise levels

For the next thermal test, I leave motherboard settings at their defaults – which results in a power limit of 200W when running Cinebench R23. CPU temperatures averaged 73.7 degrees C, which is rather impressive when you consider that our best result – with Arctic’s Liquid Freezer III Pro 420 – was only 0.1 C cooler.

150W thermal benchmarks and noise levels

For the next thermal test, I’ve set the power limit to 150W.

In this lower-intensity scenario, Be Quiet’s Silent Loop 3 slipped to third place – with an average temperature of only 59.7 C.

100W thermal results

Our next test is the least difficult benchmark featured in this review, with a workload consuming only 100W. As with the previous low-intensity test, Be Quiet’s ranking slipped – this time taking our fourth-place result. However, noise levels were dead silent – quieter than the noise meter we’re using is capable of measuring!

Conclusion

Be Quiet’s Silent Loop 3 420 offers a great combination of strong cooling and quiet performance. In stressful scenarios, it outperforms competing 360mm AIOs on the market – and in low-intensity workloads, it runs whisper-quiet – quieter than our noise meter is capable of measuring. If you’re interested in this AIO, it has an official MSRP of $189.90, but is frequently available for only $139 on Amazon.