be quiet! Silent Loop 3 420 Review: A Pricey AIO With Mighty Performance

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Hayyan Serwer

As the CPU Cooler and RAM Expert, I test the latest hardware to provide tips for smart purchases. I cover everything from busting myths about CPU coolers to looking into the newest RAM designs, examining various parts of PC hardware.

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be quiet! has released a new generation of flagship liquid coolers named Silent Loop 3. Some salient features distinguish this generation from the last gen:

• New three-chamber Pump design with enlarged cold plate design
• Silent Wings 4 PWM High-Speed fans
• 420mm variant in the new generation
• AMD TR5/sTRX4/TR4 sockets support

This generation is the epitome of what be quiet! has to offer from its arsenal as of today. This series has 240mm, 360mm, and 420mm.

This cooler is compatible with Intel LGA 115x/1200/1700/1851 and AMD AM4/AM5/TR5/sTRXS4/TR4 sockets.

Key Takeaways

• The be quiet! Silent Loop 3 420 features a new and improved three-chamber pump design and offers incredible cooling performance.
• You should buy the be quiet! Silent Loop 3 420 if you have an AMD Threadripper CPU, as the cooler is bundled with mounting hardware for it, or if you just want a really high-performance 420mm AIO.
• You should skip the be quiet! Silent Loop 3 420 if your case cannot handle a 420mm AIO or if you’re on the Intel LGA20xx platform, as the cooler is incompatible with this socket.

The MSRP of this variant is USD 174.90 and Euro 174.90 with 3 years warranty.

Here are the key specs:

Packing And Unboxing

This cooler comes inside a paperboard packing box with be quiet! standard theme. The egged carton inside the outer box has the contents. The following are provided:

• 1x Intel Backplate
• 2x Intel Mounting Brackets
• 4x Intel Backplate Screws
• 4x Locking Washers / O-Rings
• 4x Intel Spacer Nuts
• 4x Mounting Brackets Fastening Screws
• 1x AMD TR4/TR5 Mounting Bracket
• 1x set of AMD AM4/AM5 Mounting Brackets
• 4x AMD Screws
• 4x AMD Spacers
• 12x Radiator Screws
• 12x Fan Screws
• 1x Thermal Paste Tube
• 3x Zip Ties
• 1x Refill Coolant Bottle 100ml
• 1x 3-way PWM Splitter Cable
• 1x User Manual
• 1x Safety Paper

Design

Let’s take a look at the unit.

Radiator

This cooler has a 420mm size radiator. It is made of aluminum material and has an overall dimension of 457x140x52mm. 52mm height includes the fans. This means the radiator has a thickness of 27mm.

The assembly has 12 channels for coolant flow with an FPI count of 20. A gap between two opposite end holes on the main frame is 105mm. Overall build quality is satisfactory and I did not observe any bent or broken fin.

The tubes are in the center of a near block of this radiator. The connection is concealed using clamps. A sticker shows the serial number of the unit.

Like Silent Loop 2 and Pure Loop 2, this cooler also has a refill port. This port is now located near the block of the radiator and features a screw plug that is compatible with a Philips screwdriver. This makes life easy when it comes to servicing the cooler in the long run should the coolant level drop.

The side frame of the radiator housing has no branding. The far block is not as thick as the near block. The narrow gap between the fin stack and the side mounting frame is visible. This means you should be careful with the length and type of screws to be used on the radiator. So take care and preferably use the bundled screws for fans and radiator.

be quiet! uses a rubber tube with a white nylon braided mesh sleeve. These tubes have a length of 410mm and they are somewhat flexible.

Block

The pump housing or block outlook is stunning, bold, and aggressive in a good way. Be quiet! has provided us with something new and refreshing on the design side and I appreciate this change.

The complete assembly is made of ABS material and is black-finished. There is no branding on any side of the housing. This design has offset under the base.

The top of this housing features a line pattern running on entire length. It is partitioned using a cover in the center. This cover has a be quiet! branding. This cover is fixed and this limits the orientation of the block.

There is a diffuser sandwiched between the A-RGB LEDs and the top-line pattern element. The A-RGB lighting is subtle to my liking.

The rear of the block has 90ᵒ fittings on which the tubes are attached. This gives you the flexibility to adjust the tubes to some extent as per the requirement. Two single flat cables come out of the housing.

The pump is regulated using a 4-pin PWM connector. The pump is rated for 3500 RPM speed. The other connector is 5V, 3-Pin A-RGB for the A-RGB LEDs.

You can see two screws that are pre-installed on the block. Be quiet! is using a 2-point mounting mechanism on this cooler which is what I saw on the Pure Loop 2 360 and Silent Loop 2 360.

The base on this cooler is nickel-plated copper. It has a dimension of 54x41mm approximately. You can see an offset design towards the base. There is a protective sticker pasted over the base. Don’t forget to peel it off.

Be quiet! has used a three-chamber design for the pump. The cold plate has a large size and it has a high-density fin stack that helps improve the cooling performance. The pump is dampened as well. It uses a 6-pole motor.

Silent Wings 4 140mm PWM Fans

Be quiet! has used three flagship high-performance fans with this generation. This cooler comes with three Silent Wings 4 PWM High-Speed fans. Each fan has 7x blades. These blades have a striped design and they have reduced tip clearance from the frame. This provides sustained air pressure to provide high air flow. There is a ring circulating the blades. The funnel is now moved towards the rear of the fan.

These fans feature a unique feature. The anti-vibration mounts are removable and swappable. The fans with this cooler come with radiator mounts only which makes sense since these are to be used over the radiator only. This would reduce costs as well since these fans are expensive.

Arrow markers on the side frame show the direction of airflow through the fan assembly and the direction in which the blades spin.

The backside has a 4-arm assembly. These arms are in a curved layout for focused airflow. These fans use Fluid Dynamic Bearings with a life span of 300,000 hours. The Pro version of these fans comes with a speed slider which is not available with these fans.

Each fan is PWM regulated using a 4-Pin PWM connector.

Installation

The cooler is tested on MSI MEG Z790 ACE MAX motherboard using Intel Core i7 13700k. The installation steps include:

• Prepare the backplate using Intel screws and O-rings.
• Place the backplate on the motherboard’s backside.
• Use Intel Spacer Nuts to secure the backplate on the motherboard.
• Place the Intel mounting brackets on top of the Intel Spacer Nuts.
• Secured these mounting brackets using the 4x screws.
• Apply the thermal paste on the CPU.
• Remove the protective cover from the base of the cooler.
• Place the block on the CPU aligning the 2x screws on the block with the holes on the mounting brackets.
• Start tightening the screws until threads run out.
• Install fans over the radiator.
• Install the radiator assembly in the PC case.
• Connect the RGB cable to the motherboard.
• Connect the 4-pin PWM connector cable from the Pump to the water_pump or AIO_pump header of the motherboard.
• Daisy-Chain the fans and connect the 4-pin connector to the CPU_Fan header of the motherboard. You can use any 4-pin header provided it suffices to the combined power of three fans.
• Installation is completed.

Clearance

There are a few cases in the market that support a 420mm liquid cooler. This cooler has a dimension of 457x140x52mm with fans. Make sure your PC Case supports this dimension.

A-RGB Lighting

This cooler uses a standard 5V, 3-Pin A-RGB connector on the pump housing making it compatible with RGB sync technology of motherboard manufacturers including:

• ASUS Aura Sync
• ASROCK-Polychrome Sync
• GIGABYTE RGB Fusion 2.0
• MSI Mystic Light Sync

The cooler was tested on an MSI MEG Z790 ACE MAX WiFi motherboard and it was responding well to the changed in the Mystic Sync app. Here are a few pictures.

RGB Showcase

1 of 3

Testing

I have used this test bench:

• Intel Core i7 13700k [Stock, Auto]
• MSI MEG Z790 ACE MAX
• XPG Lancer RGB 32GB @ 7200MHz, CAS34
• Intel Arc B580 Card for Display
• Sabrent Rocket 4 Plus 2TB NVME SSD
• Fractal Design ION+2 860W Platinum PSU
• Thermaltake Core P6 TG Snow Edition in an open frame layout

Here is the settings table for testing:

Result

Be quiet! Silent Loop 3 420 comes on top of the graph but with just 1ᵒC difference telling us that any high-performance 360mm cooler is capable of giving a tough time to this cooler. Still, a win is a win.

This cooler was doing 42.5 dB(A) which is quite good with three fans running at full speed.

Should You Buy It?

Buy It If

✅You want a high-performance: There is no denying that this is a high-performance cooler offering a top-notch performance.

✅You have an AMD Threadripper: This cooler comes with AMD threadripper mounting hardware making it an ideal for this socket’s high thermal load design.

✅You love minimalistic lighting: This cooler is a perfect blend of an all-black theme with minimalistic A-RGB lighting. You can even turn the lighting off to enjoy a full classy look of this cooler.

Don’t Buy It If

❌You don’t have a compatible case: This cooler has a 420mm size. Make sure your case can house this size liquid cooler and can accommodate 457x140x52mm overall dimension.

❌You are still on LGA20XX socket: This cooler is not compatible with Intel LGA20xx socket. Skip it if you are on this socket.

Final Words

I have tested the Silent Loop 3 420 liquid cooler from be quiet! This is their new generation, high-performance AIO cooler. This cooler features aluminum radiator having a size of 457x140x52mm with fans. Its thickness is 27mm without fans. It is compatible with Intel LGA115x / 1200 / 1700 / 1851 and AMD AM4 / AM5 / TR5 / sTRX4 / TR4 sockets.

This radiator has a refill port and there is a 100ml coolant bottle included to service this cooler in the long run. The nylon braided-sleeved rubber tubes have a length of 410mm. The pump is rated for a 3500 RPM speed and is PWM regulated.

The pump housing has a bold, stylish outlook. It features subtle A-RGB lighting on the top. The be quiet! branding text over the top is fixed. This limits the orientation of the cooler. Be quiet! has used a three-chamber pump design with a revised cold plate to maximize the performance.

This cooler comes with three flagship fans namely Silent Wings 4 PWM High Speed. They feature removable mounting corners as per the required installation and have a reduced tip clearance from the frame to provide sustained high pressure while delivering the airflow.

Their speed rating is up to 1900 RPM. The airflow rating is 78.4 CFM at 12VDC. The air pressure rating is 2.36mmH₂O at 12VDC. Be quiet! uses Fluid Dynamic Bearings with a life span of 300,000 hours. These fans are PWM regulated.

Installation of this cooler is no different than the Silent Loop 2 or Pure Loop 2. I was hoping for a more streamlined revised mounting mechanism. I have tested this cooler on an Intel LGA1700 socket. It requires 19 items to install the block over the CPU.

Be quiet! Silent Loop 3 420 has an MSRP of USD 174.90 | Euro 174.90. This is a steep price. Probably the high price of fans is a contributing factor here. This cooler has a good performance albeit marginal when compared to the high-performance 360mm coolers. Again, the pricing would be important to determine the overall value.

This cooler comes with a 3-year warranty.

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Hayyan Serwer

[CPU Coolers & RAM Expert]

Hayyan Serwer is a tech enthusiast, with a love for PC building and article writing. Hayyan specializes in writing about CPU coolers and RAM kits. Hayyan has been familiar with the tech industry for over half a decade now, and has now stepped into providing quality reviews for the latest and greatest tech.
Get In Touch: hayyan@tech4gamers.com