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Fractal Design is a leading designer and manufacturer of premium PC hardware including cases, cooling, power supplies, and accessories. Fractal Design was established in 2007 and ever since they have come out being among the major manufacturers of high-end PC components. They are based in Gothenburg and with offices in the US as well as Taiwan, Fractal Design has gained a global reputation for innovative design, elegant aesthetics, and solid build quality. Fractal Design products are available in over 45 countries worldwide and are still growing. The Define R2 was the turning point for the manufacturer as that chassis gained the reputation and trust that is now a hallmark of the Fractal Design.

We recently did a round-up content on the high-end air coolers. It was quite a success and based on the community’s feedback we are planning another round-up content. This time the round-up content is on the best 240mm AIO coolers. We have chosen this size of the liquid cooler as it is still the most commonly used size in the liquid cooler category out of other available sizes which are 120mm, 280mm, and 360mm. We have reached out the over 30 brands and set ourselves a minimum of 15 coolers for the test. We are nearing our mark as the deliveries have started. We reached out to Fractal Design and the next we know, the Prisma was on our doorstep!

The Celcius+ is the next iteration in the liquid cooling line from the Fractal Design taking the innovation of the Celcius series to the next level using the Asetek 6th generation pump design and some effective features which differentiate the Celcius+ from the competition. Celcius+ series of the coolers are available in 240, 280, and 360mm sizes and come with two options. One option is using the RGB fans and the other option is with non-RGB fans. I will be taking a look at Celcius+ S24 Prisma RGB cooler. Celsius+ takes AIO water cooling to a new level with an ARGB-accented pump face, a fully redesigned block, and an upgraded on-radiator PWM fan hub with ARGB support. The salient features are:

  • Tinted glass pump face with backlit logo and ARGB LED effects
  • Smart auto control mode dynamically adjusts fan and pump speeds for the ideal balance of silence and cooling performance
  • Twist the pump face to change from auto to PWM mode for full user control
  • ARGB-enabled PWM hub places all fan connections directly on the radiator for a clutter-free installation
  • Sleeved tubing with concealed wiring connects power and ARGB for the entire system at the pump
  • Asus AURA, Gigabyte Fusion, MSI Mystic Light, Razer Chroma, and ASRock Polychrome support
  • Pre-applied thermal paste guarantees optimal application with even coverage
  • Low-permeability rubber tubing with nylon braided sleeves for extra durability and an added touch of style
  • Articulating elbow fittings make tubes easier to route while reducing tension on the pump
  • Prisma ARGB PWM fans deliver outstanding airflow with brilliant lighting effects (Prisma versions only)
  • Specially designed fan blades and outer ring produce a uniform glow (Prisma versions only)
  • Optimized fan geometry balances airflow with extra emphasis on static pressure
  • Trip Wire technology reduces blade turbulence
  • LLS (Long Life Sleeve) fan bearings provide silent operation with a long lifespan
  • Backed by a 5-year warranty for extended peace of mind

Item:                                     Celcius+ S24 Prisma

Manufacturer:                  Fractal Design


Source Price
NewEgg USD 163.99
Amazon USD 164
Scan UK £129.98


Specs 2

Packaging and Unboxing

The cooler is shipped inside a white color cardboard packing box.

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The cooler is designed in Sweden. The picture of the cooler is highlighting its RGB design on the block and the fans.

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The Fractal Design Celcius+ S24 Prisma carries 5 years 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:

  • Glass top with RGB LED ring
  • Automatic Temperature Control
  • Auto/PWM Control Mode
  • PWM/RGB Hub
  • Prisma AL-12 RGB PWM Fans

P3 Copy

S24 is a pre-filled CPU water cooling system.

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Salient features are printed in 24 languages. EAN and UPC stickers are printed on the side.

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The dimension of the radiator is provided on the block diagram. The socket compatibility information is provided as well. There is mentioning of compatibility with Intel LGA1200. Since that socket has the same mounting spacing as is on the LGA115x, the cooler should be compatible.

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


Contents Copy

Following are included in the box:

  • 1x 240mm Radiator and pump unit
  • 2x Prisma AL-12 RGB PMW Fans
  • 1x Intel Backplate
  • 1x Intel Mounting Ring/Bracket
  • 1x AMD Mounting Ring/Bracket
  • 1x AMD Fastener
  • 4x Intel LGA20xx Screws
  • 4x Intel LGA1200/115x Screws
  • 8x Long Screws
  • 8x Small Screws
  • 8x Washers
  • 1x RGB Cable
  • 1x User Manual

The user manual is detailed and thorough with illustrative pictures and much more information than one can expect. My praise to Fractal Design for coming up with such an illustrative manual.

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. “Celsius+ takes AIO water cooling to a new level with an ARGB-accented pump face, a fully redesigned block, and an upgraded on-radiator PWM fan hub with ARGB support. Cleverly concealed wiring in the Celsius’ braided sleeve tubing cleanly connects both power and RGB for the entire system at the pump, and selectable auto/PWM modes offer smart, dynamically optimized performance with the choice of full user control for expert fine-tuning. Available sizes include 240 mm, 280 mm, and 360 mm, each with a choice of Dynamic X2 or Prisma ARGB fans pre-installed.”

The cooler is compatible with Intel LGA20xx/1366/1200/115x sockets and AMD AM4/AM3+/AM3/AM2+/AM2/FM2+/FM2/FM1 sockets. It is also compatible with the AMD TR4 socket using the bracket included in the AMD Threadripper box.


The Fractal Design Celcius+ S24 Prisma is a 240mm CLC cooling solution. It has a 240mm radiator with 2x Prisma AL-12 RGB fans.

Rad1 Copy

The dimension of the radiator is 284 x 122 x 31mm. The thickness of the radiator is 31mm. With 25mm fans the overall thickness would be 56mm. The radiator has a 20 fins per inch one (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 22mm. Similarly, the distance between the uttermost mounting holes to the near head is 37mm.

Rad2 Copy

The radiator is made of aluminum hence it is lightweight. This is an Asetek design based on their 6th generation. The blocks on both ends of the radiator are not rectangular and have rounded edges. Fin stack is dense and taking into account the left and right side channels, it has a total of 11 channels for water flow. The fan screw threads rating is 6-32.

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I admire the attention to the details from Fractal Design as we have protective plates under every mounting hole on the radiator. This protects the radiator’s fin assembly from getting damaged if the screws are long pressed inside. I have been particularly looking for this aspect on other AIO solutions in the market and this is the second brand that I have found to be that detailed with their design. The first one is the Alphacool.

Rad2 1 Copy

The radiator assembly has a nice clean finish all around. The reason we are seeing a 31mm thickness is probably due to the fact that they have deployed the protective plates under the mounting holes. The fin assembly itself would still be Asetek’s standard size.

Rad3 Copy

The build quality of the cooler is top-notch all around. Fractal Design is using straight rotary fittings on the radiator with large size couplings. This large size could increase the overall thickness of the assembled cooler.

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There is a sticker pasted on the far head showing the part no and the serial no of the unit. The power rating is printed at 7w using 12VDC.

Tube Copy

The Fractal Design is using low-permeability rubber tubes. These tubes run to approximately 400mm in length and have braided nylon sleeve on them. The tubes are thicker as compared to other CLCs from Asetek and there is a good reason for that. This cooler features an integrated hub on the radiator with an ARGB cable and a PWM cable coming off the hub. Fractal Design has passed these cables along the tubes inside the sleeves. The result is we have a neat and clean look on the cooler with the magic of hidden cables.

Rad4 Copy

There is an integrated hub on the radiator housing. It has a black color PCB. The ports on the hub are:

  • 2x ARGB LED headers (3-pin, 5V)
  • 4x 4-pin PWM headers

Since 1 header of each type is already in use, the user can connect only 1 ARGB device and up to 3x PWM fans to the hub.

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Here is the top view of the hub. The PCB is labeled. The fan is written against the 4-pin PWM headers and the LED is written against the 2x ARGB headers. Please, note that I have removed the connectors when taking this picture.


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We have a circular shape dual layered housing on the block. The housing is black in color. The top section has a tinted glass pump face with a backlit Fractal Design logo and an ARGB ring using 6 LEDs. PWM and Auto can be seen on the left side. These are white color LED indicators that remain off and comes on only when the switch is flicked. The Fractal branding remains visible and under lighting all the time. The ring can be seen on the edge of the housing border. The Intel mounting ring/bracket is pre-installed on the housing. The dimension of the block is 86x75x45mm with fittings. The block diameter is 62mm with a black body.

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There is a 3-pin header on the side of the housing. This is where the ARGB cable is connected to. The housing section below this header protrudes making a dual-layer design. The top section is rotatable. Rotating it will switch the thermal performance mode from Auto to PWM and vice versa.

Block3 Copy

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 are right on the money.

Block3 1 Copy

The RGB and PWM cables are coming out of the tube endings on the block and are routed in the housing of the block. The execution is flawless.

Block4 Copy

There is a cable coming out from the front side of the pump housing. It is braided as well. I would have loved to see a flat cable but this is my personal preference.

Block6 Copy

The cable has a 4-pin PWM connector.

Block5 Copy

This side of the housing has a plain surface. The base below the main housing has latches which is Asetek standard design. This is where the Intel/AMD mounting rings are installed.

The Fractal Design Celcius+ S24 Prisma features a 6th generation pump from Asetek with customized PCB from Fractal Design. Here are some technical data of the pump:

Speed 800~2800 RPM in Normal Mode. 3500 RPM in Thermal Protection Mode when the temperature of the coolant crosses 60°C.
Bearing Ceramic Bearing and Shaft
Acoustical Noise 20 dBA at full speed
Pressure at 50°C 14.4 KPa / 1.46 mmH₂O / 2.0 PSI
Input Voltage 12VDC
Input Current 0.37A
MTTF 50,000 hours (permeation life at typical use)
PWM Control Yes
Liquid Flow Rate 40 L/H at 50°C


Base Copy

We have a copper base with a pre-applied thermal paste. Our recent testings are showing that Asetek has lifted their game with TIM as new coolers are showing similar thermal performance using Asetek stock TIM as is with the Noctua NT-H1.


Fan1 Copy

The Prisma version of the S24 carries the AL-12 RGB PWM Prisma fans. These are high airflow and static pressure rated fans. Each fan has 7 white color (not translucent) blades with optimized fan geometry balancing the airflow with extra emphasis on static pressure. There is a Fractal Design branding on the sticker in the middle. There is an outer ring on the frame as well for the uniform glow of ARGB lighting. The ring is only on the top side and does protrude to the rear side of the frame. There is an anti-vibration padding on each mounting corner.

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One side of the frame has two arrow symbols. These help the user in identifying the direction of airflow and blades’ spin direction.

Fan3 Copy

There is Fractal Design branding on one side.

Fan4 Copy

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

Fan5 Copy

There are two sleeve cables coming out of the fan. One is the 4-pin PWM fan connector and the other is a dual header cable for ARGB lighting. The dual header design allows the user to daisy chain the cables and uses a single connector to power the complete assembly.

The specification of the fans are:

Dimension 120x120x25mm
Type 4-pin PWM Connector
Speed 500-2000 RPM
Airflow 85.71 CFM
Air Pressure 2.78 mmH₂O
Noise 32.7 dB(A)
Bearing Type LLS
Lifespan 100000 hours
Input Voltage 12VDC
Input Current 0.18A
ARGB Connector 5V,3pin ARGB dual Header


Fractal Design has provided 2x catchers with adhesives. Use them on the radiator assembly to house the Prisma fans’ cables when routing towards the integrated hub for neat cable management.

Backplate Copy

The Fractal Design Celcius+ S24 Prisma comes with Asetek standard backplate for Intel sockets excluding the LGA20xx.

Intel Copy

The Intel mounting bracket/ring is pre-installed on the pump housing.

AMD Copy

The AMD mounting bracket/ring has one latched end and the other straight end. It uses the AMD stock backplate. The latch end is hooked up to the side of the AMD stock bracket. The AMD pin is inserted into the hole on the other end of the ring.

RGB Lighting

There is no dedicated controller provided with the cooler. You would need to have an ARGB lighting header on the motherboard or a compatible controller to make the ARGB lighting work on the cooler. In my opinion, there should have been a dedicated controller in this price tag. I have tested the cooler on ASUS ROG Rampage V Edition 10 motherboard which does not have a 5V header. I ended up using a controller from another cooler.


We have tested the cooler on the X99 platform using the 2011-3 socket. Installation is simple and as under:

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Install the Intel LGA20xx standoffs.

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Install the fans on the radiators. Don’t use the washers on the fans. They are to be used for the radiator mounting on the chassis.

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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.

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Connect the RGB cable to the header on the pump housing.

Daisy chain the fans and pump ARGB LED cables and connect the ARGB LED to the integrated hub on the radiator. Connect the 4-pin PWM connectors of the AL-12 ARGB Prisma fans to the headers on the integrated hub. Connect the 4-pin cable of the pump to the CPU fan header or AIO/Pump header on the motherboard.

Since the Fractal branding is fixed, the user will have to ensure that the Fractal text is facing upfront. This is kind of a limitation as we can’t rotate the text to install the block in any direction. Practically, the block can be installed in any direction but aesthetically it will not look good.

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

Testing Methodology

Following test benches have been used: –

  • Asus Rampage V Edition 10
  • Intel i7 6850k
  • Colorful GeForce GTX 1050Ti Vulkan
  • Samsung 840 EVO 250GB SSD
  • Cooler Master MWE 650W Gold
  • Custom open-air test bench

The software used for testing and monitoring include:

  • Asus Real Bench v 2.56 (Intel)
  • Real Temp GT v 3.70 (Intel)

Here is the settings table for testing:

OC Clock (MHz) 4100
OC Voltage (V) 1.21
Turbo Boost Disabled
C-States Disabled
Speed Step Disabled
Thermal Paste Noctua NT-H1
Test Run Time 60 minutes
Idling Time 15 minutes
Fan Speed Tested using Integrated Hub on the radiator at Auto/PWM

Manually set to run at 100% speed.

Auto PWM using CPU Fan Header

Pump Speed Connected to the AIO Pump header to run at 100% speed


We are using Noctua NT-H1 thermal paste for coolers 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.

Before we take a look at the results, we need to understand the two thermal modes on the Celcius+ S24 Prisma cooler. As mentioned above, by rotating the top lid of the block the thermal mode will switch from PWM to Auto and vice versa. What does it mean and what are the limitations?

In stock configuration, we have connected the fans to the integrated hub. The pump’s 4-pin cable is connected to the CPU Fan header or any other PWM 4-pin header on the motherboard.


In Auto mode, the firmware of the cooler takes over the charge and controls the speed of the fans and the pump making sure that the user is getting a quiet or silent operation. In this mode, the firmware will keep the pump’s noise at or below the fans’ noise. Remember the maximum noise rating of the pump is 20 dBA. This would mean the pump and the fans would remain at a lower noise level no matter what. We literally have silent operations under Auto mode. Any catch? Yes, there is a catch to it. We are severely undermining the thermal performance across the board as the cooler is now operating much below its rated cooling potential. Unless you are a sound freak, you would stay away from the Auto mode.


PWM modes give the user total flexibility with the condition that the liquid temperature remains within the 60°C threshold. By switching to PWM mode, we are now actually turning to the motherboard’s PWM controller of the header to which the pump’s power cable is connected to. Any catch? Yes, there is a catch to it. Since both fans and the pump are now being controlled using a single motherboard fan header, there is no way you can control the speed of the pump independently of the fans. Since we are testing all the coolers with the pump running at full speed it would have been impossible to do our routine testing. For that, we took off the fans’ cables from the integrated hub and connected them to the 4-pin PWM headers on the motherboard.

This way we have a total of 5 test runs for this cooler which is as under:-

  • PWM mode using an integrated hub
  • Auto mode using an integrated hub
  • A full-speed test of the fans using the motherboard’s fan header
  • Auto PWM speed test of the fans using the motherboard’s fan header
  • PWM mode using an integrated hub with Noctua NT-H1

Let’s take a look at the results.


4000 Full 1

In our stress test at 4.0GHz, all cores the Fractal Design Celcius+ S24 Prisma with its control using the integrated hub and the motherboard based control is sitting at no three in the graph with an overall thermal difference of just °0.8C which is meaningless. All top three contenders are in for the run of your money and offer similar performance.

4000 Auto 1

The Auto mode is where you would not want to run this cooler. The PWM profile is not that tight on these Prisma fans as they were running on 1100 RPM mark give and take. But they were silent and the performance level is adequate.


After 30 minutes of stress test (test still running), we took the thermal imaging of the block and VRM area as well as the radiator surface and blocks. There is nothing to complain about at all with the powerful cooling performance of the Fractal Design Celcius+ S24 Prisma.


The fans are loud under PWM mode and we measured them to making 55 dBA with an ambient sound level of 34 dB(A).


Clecius+ is the next iteration of closed-loop liquid coolers from the Fractal Design. The series has two offerings per size with the main difference coming from the RGB or no RGB. The Prisma series under Celcius+ comes with AL-Prisma series ARGB fans without any compromise on the performance. The Dynamic series in Celcius+ comes with Dynamic XL series fans with almost the same performance. Each series has 240mm, 280mm, and 360mm variants. Fractal Design sent us their Celcius+ S24 Prisma cooler for the review and the round-up content. This is an Asetek design using their 6th generation pump with further in-house customization to bring one feature-rich, powerful cooling solution at the user’s disposal. The cooler is compatible with Intel LGA775/1366/115x/1200/20xx sockets and AMD AM4/AM3+/AM3/AM2+/AM2/FM2+/FM2/FM1 sockets.

The unit has an aluminum radiator measuring 284 x 122 x 31mm. The thickness of the radiator is 31mm. The overall thickness would be 56mm 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 braided nylon sleeve on them. I love the attention to detail in the design of the cooler. The radiator has protective plating under each mounting hole for safety measures. This is the second AIO I am seeing with such details after Alphacool and something we don’t see in other AIOs.

There is an integrated ARGB-enabled PWM fan hub on the radiator allowing the user to connect 1x 3-pin 5V ARGB device and up to 3x 4-pin PWM fans to the hub. The cables coming off the hub are routed through the sleeves on the tubes. In other words, the cables are hidden. This is too good a smart design to have!

The block has a tinted glass pump face with backlit lighting. There is an ARGB LED ring on the block with 6 ARGB LEDs to glow it and the Fractal branding. This is not all as there are two other LED indicators as well. These are PWM and Auto. The top lid acts as a switch. Flick it to activate either of the two thermal modes. Another brilliance is the thermal sensor in the loop which is continuously monitoring the temperature of the coolant. As soon as the coolant crosses the 60°C the pump will kick the 3500 RPM speed which is otherwise not available as the pump reaches a maximum of 2800 (2700 in our case) RPM mark. Speaking of the pump, it has a ceramic shaft and bearing with a pressure rating of 2.0 PSI at 50°C and a maximum flow rate of 40 l/h at 50°C. It has a life expectancy of 50,000 hours which is permeation dependent.

The Celcius+ S24 Prisma comes with two AL-12 ARGB PWM Prisma fans. These are high airflow and static pressure optimized fans for optimal cooling performance out of the box. These fans feature a ring on the frame as well for maximum AURA of stunning ARGB light show. They are rated for up to 2000 RPM with an airflow rating of 85.71 CFM and a 2.71 mmH₂O pressure rating. They have a life expectancy of 100,000 hours using LLS bearings.

Being an Asetek design, the installation is a walk in the park. I have nothing particular to report from the installation department. I mentioned the Auto and PWM modes above. When the switch is set to Auto mode, the firmware of the cooler takes over the charge and controls the thermal aspects making sure that the pump’s noise doesn’t cross over the fans’ noise ensuring silent operations. In PWM mode the control is transfer to the motherboard’s PWM controller for the fan header in use. In other words, the user is in control now. We have one caveat here. Since the fans are connected to the hub and the only cable connected to the motherboard’s fan header is the one coming off the pump’s housing, we can’t control the speed of the fans and the pump separately. In our testing, the Auto mode is offering dead silent operations but at the expense of low thermal performance. The PWM mode is dependent upon the fan header’s fan curve settings.

The Fractal Design Celcius+ S24 Prisma is listed at $163.99 (NewEgg pricing) and £129.98 (Scan UK pricing) at the time of the review. Fractal Design is offering 5 years warranty. We have a premium price tag for the feature-rich cooling solution with good performance written on its face. Though I would love a dedicated lighting controller in this price range to be provided! 5 years warranty is showing the confidence of the manufacture in the product. With top-notch build quality, good performance out of the box, feature-rich solution, 5 years of peace of mind; the Fractal Design Celcius+ S24 Prisma is a Must-Have from Enos Tech.

Enos Tech Must Have Award

Many thanks to Fractal Design for sending in their Celcius+ S24 Prisma cooler for our 2021 AIO cooler roundup comparison. We’ve reached out to most major brands in an effort to compare the best AIO coolers of 2020 against each other and let you know which ones come out on top. Please make sure to check out our 2021 AIO COOLER ROUNDUP and again, thanks to all the companies taking part. Below is the listing of the coolers confirmed so far.

Brand Website  Cooler Review
AZZA Blizzard 240
SilverStone IceGem 240
Fractal Design Celcius+ S24 PRISMA
CORSAIR H100i RGB Platinum
Antec Neptune 240
XPG Levante 240
ARTIC Liquid Freezer-II
EK Water Blocks EK-AIO 240
ID-Cooling Aura Flow X 240
Cooler Master Master Liquid ML240L ARGB V2
Enermax Aquafusion 240
DeepCool Castle 240EX White
AeroCool P7 L240 or Mirage 240
Reeven Naia 240
Lian Li Galahad
be quiet! Pure Loop 240

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