Fractal Design has recently launched its new series of AIO coolers named Lumen. This time around, they have switched to APALTEK as the OEM of the Lumen series coolers. Fractal Design has sent us Lumen S24 RGB and Lumen S36 RGB coolers for testing. These coolers are available in RGB as well as non-RGB versions though do note that the non-RGB versions still have A-RGB lighting on the block. We will be spinning Lumen S24 RGB in this content. The salient features are:

  • Integrated ARGB effects with full motherboard control
  • Removable pump face can be turned at 90-degree intervals to maintain a horizontal logotype in
  • any mounting orientation
  • Asus AURA, Gigabyte Fusion, MSI Mystic Light, Razer Chroma and ASRock Polychrome support
  • Pre-applied thermal paste for optimal application with even coverage
  • Supports the most common sockets for both Intel and AMD
  • Durable low-permeability rubber tubing with nylon braided sleeves
  • Articulating elbow fittings make tubes easier to route and reduce tension on the pump
  • Low turbulence Fractal Design Aspect fans with chainable power and ARGB connectors
  • Backed by a 5-year warranty

Item:                                     Lumen S24 RGB

Manufacturer:                    Fractal Design

Price:                                     $109.99 MSRP

Amazon UK:                         £115.55



Packaging and Unboxing

The cooler is shipped inside black and white colors cardboard packing box.

The RGB Lighting is compatible with:


The Fractal Design Lumen S24 RGB comes with a 5-year warranty which is too good to have on a premium cooling solution and it shows the trust of the manufacturer in their product. The salient highlights of the cooling unit are:

  • Duality Design
  • Six A-RGB LEDs
  • The Removable Top
  • Pre-Applied Thermal Paste
  • Aspect Fans

The dimension of the radiator are provided on the block diagram. The socket compatibility information is provided as well.

There is a Styrofoam pad on the top along with the user guide.

There is an egged carton inside the main packing box. Contents are placed in that carton.


Let’s take a look at what is provided in the box.

  • 1x Comprehensive User Manual
  • 1x Brochure on how to contact the manufacturer in case of receiving the faulty product.

  • 1x Intel Backplate
  • 1x AMD Ring Bracket
  • 1x Intel Ring Bracket [Comes pre-installed on the block]

  • 4x Thumb Nuts
  • 4x Black Spacers
  • 4x Intel LGA20xx Standoffs
  • 4x Intel other sockets Standoffs
  • 5x Washers
  • 2x AMD Mounting Brackets (Pins)

  • 8x Philips 6-32 Long Screws
  • 8x Philips 6-32 Short Screws

1x Cable is provided which connects the block of the cooler with the standard 3-pin A-RGB header (5V) header on the motherboard.


Closer Look

It is time to take a closer look at the components. Before that here is what Fractal Design is saying about the cooler. “The new Lumen series of AIO CPU coolers from Fractal Design delivers high-end cooling performance and premium ARGB effects at an attractive price. Lumen features Fractal Design’s newly released Aspect PWM fans with daisy-chainable power/ARGB connectors and comes pre-applied with optimal thermal paste coverage, making it an attractive AIO solution for both starting and seasoned builders. Options for controlling the pump’s integrated ARGB effects include Asus AURA, Gigabyte Fusion, MSI Mystic Light, Razer Chroma, and ASRock Polychrome support. 240mm, 280mm, and 360mm radiator sizes are available with a choice of ARGB or all-black Aspect fans, and all versions include mounting hardware for all the most common AMD and Intel CPUs as well as a 5-year limited warranty.”

The cooler is compatible with Intel LGA20xx/1366/1200/115x sockets and AMD AM4/AM3+/AM3/AM2+/AM2/FM2+/FM2/FM1 sockets.


The Fractal Design Lumen S24 RGB is a 240mm CLC cooling solution. It has a 240mm radiator with 2x Aspect 12 RGB PWM fans.

The dimension of the radiator is 272 x 120 x 27mm. The thickness of the radiator is 27mm. With 25mm fans, the overall thickness would be 52~53mm. The radiator has 20 fins per inch (FPI). There is a gap of 105mm between any two fan mounting holes on the radiator. The distance between the middle two mounting holes is 15mm and the distance from the outermost mounting hole to the far head is 20mm. Similarly, the distance between the uttermost mounting holes to the near head is 27mm. Fin stack is dense and taking into account the left and right side channels, it has total 12 channels for water flow. The fan screw threads rating is 6-32.

Radiator is made of aluminum hence it is lightweight. This is an APALTEK design. The blocks on both ends of the radiator are not rectangular and have rounded edges.

We have nice and clean fins stack.

Unlike the Celcius+ series, the Lumen series radiators don’t have protective plating under the fin stack which would prevent the screws damaging the fins.

There is a Fractal Design branding the sides of the radiator housing.

The build quality of the cooler is top notch all around. Fractal Design is using barbed fittings on the radiator with large size couplings. There is a sticker pasted here showing the serial no of the unit. There is what seems to be the drain port or something. It is reserved for factory use only and opening it might lose the vacuum pressure in the loop.

The Fractal Design is using low-permeability rubber tubes. These tubes run to approximately 400mm in length and have a braided nylon sleeves on them.

Unlike the Celcius+ series coolers, the Lumen coolers don’t have a PWM/ARGB hub on the radiator. But there is one key difference here. The Pump is installed on the radiator instead. I think NZXT was the one who launched similar design back in time. Here is some data pertaining to the pump:

Rotational Speed 4000 ±10% RPM
Bearing Ceramic
PWM Control No
Noise at full speed 22 dBA
Maximum pressure, 50°C 2.5 PSI
Rated Voltage 12VDC
Rated Input Current 0.34A
Rated Input Power 4.08W
MTTF 50,000 Hours
ARGB Cable Length 500mm

There is a 3-pin cable coming out of the pump. It has a length of 775mm which is plentiful to reach the desired control source even if the radiator is mounted on the front of the PC case.

The routing of the pump power cable has been done wisely. There are two cutouts on the sides of the housing of the radiator. Cable can either be route through these cutouts for neat cable management.


The block of the cooler is a lightweight which makes sense as we only have cold plate, chambers for the coolant flow and top cover with 6 A-RGB LEDs under it. The dimension of the block is 79x67x43mm where 43mm is the height of the block and 67mm is the diameter. The dimension is inclusive of the tube fittings.

The top cover is not in a solid color and there is a reason for that. It is translucent with supported PCB and A-RGB LEDs on the PCB. The top cover is removable and can be placed in 90° rotations which makes the installation of the block irrespective of the logo.

The above pictures show the top cover placed in three angle besides the default location.

The main housing of the block is in matte black. Notice the spacing below the housing and above the base. This is where the Intel/AMD mounting rings are slided in.

Fractal Design is using articulating 90° elbow fittings on the block. This makes the rotation of the tubes easier and reduces the tension on the pump. The machining and milling is right on the money.

There is a 3-pin header on the side of the main housing. This is where the provided 3-pin ARGB cable is connected to power the ARGB LEDs.

We have a copper base with pre-applied thermal paste. We are not testing the cooling solution on stock paste as our standard thermal paste is Noctua NT-H1.

The above picture shows the complete copper base with thermal paste removed.


The RGB version of the Lumen S24 carries the Aspect 12 PWM RGB fans. These are high airflow and static pressure fans. Each fan has 7 semi-opaque white color blades with optimized fan geometry balancing the airflow with extra emphasis on static pressure. Here are key features of the fans:

  • Efficient rifle bearings with 90,000 hour MTTF
  • 6 individually addressable hub-mounted RGB LEDs (RGB versions)
  • Supports ASUS AURA, Gigabytes Fusion, MSI Mystic Light and ASRock Polychrome (RGB versions)
  • Aerodynamic stator with embedded wiring reduces turbulence
  • Trip Wire technology introduces a micro-turbulent layer for enhanced blade efficiency
  • Daisy chainable power and RGB wires for easy hookup
  • PWM control with a wide speed range
  • High static pressure ideal for radiators and airflow-restrictive applications

The mounting corner’s inner side has an arrow symbol showing the direction of the airflow.

There is Fractal Design branding on one side.

The backside of the fan shows the 4-arms assembly on the mainframe with one arm having an inset. The wires are routed on this arm towards the exterior of the fan. There is a Fractal Design branding on the sticker in the center.

The fans have a 4-pin PWM connector and header/socket. They also have a 3-pin 5V ARGB connector and header/socket for easy daisy-chaining. The cables are flat in design.

The specification of the fans are:

Dimension 120x120x25mm
Type 4-pin PWM Connector
Speed 500-2000 RPM
Airflow 13~56 CFM
Air Pressure 0.23~2.34 mmH₂O
Noise Up to 32.2 dB(A)
Bearing Type Rifle
Lifespan 90000 hours
Input Voltage 12VDC
Input Current 0.37A
Starting Voltage 7V
LED Input Power 1.50W
LED Input Current 0.30A
LED Input Voltage 5V
Cables Length 500mm



We have tested the cooler on our recently upgrade test bench using Intel Z490 chipset with LGA1200 socket. Installation is as under:

Prepare the backplate by passing the Intel LGA1200 standoffs through the designated holes. Use the washers to secure the standoffs.

Place the backplate on the motherboard’s socket area.

Place the black color spacers on the standoffs. You should feel the mounting pressure of these spacers otherwise you are doing it wrong.

Connect the ARGB cable to the housing of the block.

Place the block on the CPU by aligning the holes on the mounting bracket with the threaded sides of the standoffs.

Use the thumb nuts to secure the installation. Please note that Intel mounting ring is pre-installed on the block.

Install the fans on the radiator.

Connect the 3-pin pump connector to the pump header on the motherboard. Daisy chain the 4-pin PWM connectors and connect the chained solution to a CPU Fan Header on the motherboard. Repeat the same for the ARGB connectors and connect on the ARGB 5V header on the motherboard which in our case is JRAINBOW2 on the MSI MAG Z40 TOMAHAWK.

Install the radiator in the PC Case. This would complete the installation.

There is no clearance issue with respect to the DIMM slots and first PCIe slot. Make sure your chassis has clearance for a 240mm radiator (with a total length of 272mm).


Following test bench is used: –

  • Intel i7 10700k
  • T-Force NightHawk RGB 16GB @ 3200MHz
  • Nvidia GeForce GTX 1080 FE
  • addlink S70 256GB NVMe SSD
  • Fractal Design ION+ 860P PSU
  • Open-air test bench

Here is the settings table for testing:

Clock (MHz) 3800 All Cores
Voltage (V) 1.025
Clock (MHz) 4700 All Cores
Voltage (V) 1.255
Clock (MHz) 5100 All Cores
Voltage (V) 1.345
Turbo Boost Disabled
C-States Disabled
Speed Step Disabled
Thermal Paste Noctua NT-H1
Thermal Paste Application Dot Method in the center.
Test Run Time 30 minutes
Idling Time 10 minutes
Fan Speed 100% PWM Duty Cycle and Auto PWM
Pump Speed Connected to the AIO Pump header to run at 100% speed
Header CPU_Fan header for the fans and Pump_Header for the pump
Software AIDA64 6.3 Extreme [FPU]


We are using Noctua NT-H1 thermal paste for cooler testing. Using the same thermal paste for all coolers would ensure standardization. Delta temperatures are reported on the graphs. The testing is done on an open air bench system. Once inside the chassis, the temperatures are expected to rise and would largely depend upon the optimal airflow inside the chassis.

Not every run of the stress test may yield the same result. This could well be due to many factors like mounting pressure, thermal paste application, varying ambient temperature. Not to mention the silicon differences even among the same category of the chips. Hence, it is pertinent to mention the testing methodology along with the specifics.

The coolers are also tested using the Auto PWM function. MSI is using Smart Fan mode in the UEFI/BIOS which is not pure Auto PWM but it is what is available to us. The above picture shows the MSI default fan curve for the Smart Fan mode. Since all the coolers will be tested using the same configuration and settings, the same margin of error applies to all.

Let’s take a look at the results.

3.8GHz All Cores

4.7GHz All Cores

4.7GHz All Cores [Auto PWM]

Fans’ Speed on Auto PWM

The above graph shows the maximum speed attained by the fans on the Auto PWM. For comparison, we have included the rated speed of the fans to have a reference in determining the Auto PWM range. The Aspect12 PWM RGB fans are rated for 2000 RPM. On Auto, PWM they attained the maximum speed of 1913 RPM at much better sound level than is on the full speed.

5.1GHz All Cores

We have a comparable performance from the Fractal Design Lumen S24 RGB.


The sound meter was showing the noise level to be 50 dB(A) with an ambient sound level of 32 dB(A).



Lumen is the new series of AIO coolers from the Fractal Design using APALTEK as OEM. The new series has two categories of coolers. One is RGB and the other is non-RGB. These coolers are available in 240mm, 280mm, and 360mm sizes in both categories. Another keynote is the launch of new Aspect series fans from the Fractal Design in 120mm and 140mm sizes in black and white colors. The Lumen coolers take full advantage of Aspect fans as they feature Aspect 12/14 RGB PWM fans in Lumen S RGB coolers and non-RGB Aspect fans in the Lumen S RGB coolers.

We took a look at Lumen S36 RGB earlier. Click here to check its content. This time we have tested the little brethren Lumen S24 RGB. The Lumen S24 RGB has wide socket compatibility as it supports Intel LGA/1366/115x/1200/20xx sockets and AMD AM4/AM3+/AM3/AM2+/AM2/FM2+/FM2/FM1 sockets.

The unit has an aluminum radiator measuring 272 x 120 x 27mm. It is black in color spray painted. The thickness of the radiator is 27mm. The overall thickness would be 52~53mm after installing the fans. The radiator has 20 FPI. The Fractal Design is using low-permeability rubber tubes running to approximately 400mm in length and has a braided nylon sleeve on them. The radiator does not have a protective plating under each mounting hole for safety measures.

Another striking difference in this new series over the previous series is the lack of an integrated fan/RGB hub on the radiator. The pump on Lumen S24 RGB has been integrated into the radiator. Fractal Design was paying close attention as they have provided purpose-built cutouts on the housing of the radiator on both sides through which the user can route the power cable coming from the pump. The pump takes power from a 3-pin connector. The pump has a ceramic shaft and bearing with a pressure rating of 2.5 PSI at 50°C. It has a life expectancy of 50,000 hours which is permeation dependent.

The block has a circular shape and is quite lightweight. The top cover serves the Duality design. We have an almost brown-colored top cover which is in fact translucent. There are 6 ARGB LEDs underneath which illuminates the complete top in one heck of an AURA show. The top cover is also removable and can be placed at 90° angles. This makes the placement of the block independent of the brand logo’s orientation. There is a detachable ARGB cable provided in the box which the user can connect to the block and the other end to the 5V, 3-pin header on the motherboard.

The Lumen S24 RGB comes with two Aspect 12 RGB PWM fans. These are high airflow and static pressure optimized fans for optimal cooling performance out of the box. These fans feature A-RGB lighting. They are rated for up to 2000 RPM with an airflow rating of 56 CFM and 2.34 mmH₂O pressure rating. They have a life expectancy of 90,000 hours using Rifle bearings.

The coolers based on Asektek’s design have a convenient installation. With APALTEK as OEM, we were dealing with some 18 mounting hardware pieces with roughly 6 steps to install the block on the CPU. Still, the installation was not tough at all and we were able to install the cooler in a few minutes. Since the Lumen S24 RGB cooler is using standard 3-pin, 5V connectors for the ARGB lighting and the provision of sockets on the cable allows the user to easily chain the fans the block so that the lighting effects and speed of the fans can be controlled from a single source i.e 4-pin PWM header and 3-pin 5V header on the motherboard. Please note that there is no dedicated controller provided in the box.

The Fractal Design Lumen S24 RGB is listed at $109.99 MSRP at the time of the review. Fractal Design is offering a 5-year warranty. The cooler has performed quite well to tame the temperatures of Intel i7 10700k at high synthetic loads with heavy overclocking. The noise output is also good. The Lumen S24 RGB brings a good value proposition that is balanced across pricing, noise, and thermal performance. This is further augmented with brilliant ARGB lighting and peace of mind would come with a 5-year warranty.

Thanks to Fractal Design for the sample provision of Lumen S24 RGB for testing.