Fractal Design Celsius S24 Feature

Introduction & Closer Look

Since Fractal Design launched its Kelvin range of all-in-one CPU water coolers back in 2014, several of their competitors have launched new updated models, whilst the Kelvin remained unchanged. Now in 2017, Fractal have re-joined the party, with the release of the Celsius. With new coolers constantly setting new benchmarks in our performance charts, we have the 240mm Celsius S24 on the test bench, to put it through its paces.

Fractal Design Celsius S24 Box

Perhaps the biggest difference between the new Celsius series and the aging Kelvin, is that Fractal Design have this time gone with Asetek as the base provider of the technology. The Kelvin previously featured a copper radiator supplied by Alphacool, but by jumping to Asetek this time around, that is replaced by an aluminium construction. With other companies using Asetek as their supplier, there is a lot of familiarity here with regards the mounting brackets, and general design of the unit.

Fractal Design Celsius S24 Contents

The Celsius S24 has support for all the major Intel and AMD sockets, including AM4. We are still receiving coolers that don’t support Ryzen out of the box, so it’s nice to see that Fractal has this covered. The sockets supported are:





Fractal Design Celsius S24 Block

Taking a closer look at the CPU block, we start to see the really big advancements that Fractal Design have included with the new Celsius range. The design of the pump housing now features a glossy finish, with a subtle nod to Fractal’s snowflake branding embossed into it. The real star of the show here though is the ability to twist the outer ring of the block, to switch between Auto and PWM mode in the coolers operation.

This very tactile approach means that no separate software is required, but instead this switch determines whether your BIOS or the internal Asetek firmware is responsible for the coolers operation. For the purposes of our tests, we will be setting the Celsius S24 to Auto mode.

Fractal Design Celsius S24 Baseplate

Flipping the pump over, and we see that the coldplate is the usual Asetek standard fare here, and is made entirely of copper. Thermal paste comes pre-applied, but we will be cleaning this off anyway to apply Noctua’s NT-H1 that we use in all of our CPU cooler tests.

Fractal Design Celsius S24 Fittings

On closer inspection of the radiator, we find another of the crown jewel features of the Celsius S24.  Attached directly to the radiator we have an integrated fan hub, so that both fans can be connected directly, rather than need to be routed to a header on the motherboard. Not only that, but the cable from the pump also connects into this hub, and is concealed within the tubing sleeve itself. This is a very clever idea indeed, and given it’s such a simple idea, I’m surprised we haven’t seen this before.

A further enhancement is the standard G 1/4” thread connectors applied to the tubes, which as well as giving the Celsius S24 a nice premium feel, also caters for anyone who wants to expand their cooling solution to include a GPU block. It’s worth noting here though that whilst the Celsius comes with a 5 year warranty, if the customer decides to expand the unit, only individual components of the Celsius are covered.

Fractal Design Celsius S24 Fans

Bundled with the Celsius S24 are two of Fractal’s Dynamic X2 GP-12 120mm fans, that come with 4-pin PWM connectors, and white fan blades. The speed adjustment of these fans range from 500 to 2000 RPM, to ensure the best noise to performance ratio dependent upon the load the cooler is put under.



  • Coldplate technology: Fifth generation
  • Coldplate material: Copper
  • Additional sound dampening: Integrated
  • Thermal paste: Pre-applied, high thermal conductivity
  • Tube length: 400 mm
  • Tube material: Sleeved low-permability rubber tubes
  • Fittings, block side: Durable metal fittings, non-removable
  • Fittings, radiator side: Durable metal fittings, G 1/4″ thread
  • Thermal paste: Pre-applied, high thermal conductivity
  • Fan control: Integrated dual mode

Fan Specification

  • Fan type: Fractal Design Dynamic X2 GP-12 PWM
  • Rotational speed: 500-2000 RPM
  • Bearing: LLS bearing
  • PWM control: Yes
  • Acoustical noise (full speed): 32.2 dB(A)
  • Maximum air flow: 148.8 m3/h | 87.6 CFM
  • Maximum static pressure: 2.30 mm H2O
  • Input voltage: 12 V DC
  • Maximum input current: 0.2A
  • MTBF: >100,000

Pump Specification

  • Rotational speed: 1950-3150 RPM
  • Bearing type: Ceramic bearing and shaft
  • PWM control: Yes
  • Acoustical noise (full speed): 20,0 dB(A)
  • Maximum pressure, 50°C: 1m H2O | 1.45 PSI
  • Input voltage: 12 V DC
  • Input current (without fans): 0.15 A
  • Rated input power (with fans): 6.6W
  • MTTF: >50,000 hours

Radiator Specification

  • Dimensions: 284*122*31 mm
  • Housing material: Aluminium
  • Fin material: Aluminium
  • Port threads: G 1/4″
  • Fan screw threads: UNC 6-32

Thermal Performance

Since our previous cooling reviews prior to November 2016, we have decided to update the method accordingly for better and consistent results. It isn’t ideal running Prime95 for a prolonged period of time and if you get called away to do something, it could be left running for much longer than needed. Our new methodology involves running a very stressful multi-threaded performance benchmark called ROG RealBench.

It should also be noted that the reason we omit acoustic/noise testing is due to an inaccuracy within the readings and method. To provide truly accurate readings, you need a lab setting with the same ambient noise on an hour by hour, day by day and week by week basis. As ambient noise can increase at different times of the day, we believe that it’s pointless providing noise testing if we can’t measure consistent and accurate data due to our office being a busy setting.

Test Setup

Idle Testing Methodology

To test each cooler at idle, the minimum temperature is taken after leaving the PC with only start-up programs on Windows 10 being allowed to run for 5 minutes. After this, the minimum temperature with the core temperature being offset against the room temperature; thus achieving delta.

Load Testing Methodology

To load test, we run RealBench while selecting the heavy multitasking benchmark only. We run this a maximum of 3 times concurrently and the maximum temperature recorded is taken. This temperature is deducted from the current room temperature and our final delta temperature is provided.


Fractal Design Celsius S24 4.2Ghz idle

Fractal Design Celsius S24 4.2Ghz load

Fractal Design Celsius S24 4.5Ghz idle

Fractal Design Celsius S24 4.5Ghz load



As you can see from the charts above, the Fractal Design Celsius S24 is a really strong performer. It traded blows with it’s counterpart from Cooler Master, which is a firm favourite of mine personally. It didn’t get close to the chart topping Silent Loop 360, but I didn’t expect it too given that the S24 is only a dual fan cooler, with a radiator that is only two thirds of the size of the bequiet! offering.


The Celsius S24 scores really highly in the design stakes. The introduction of the integrated fan controller on the radiator itself is quite frankly, genius! The simple ability to switch from Auto to PWM modes with a twist of the pump casing is also a nice touch. Obviously you would need to reach inside your case to do this, but I wouldn’t expect the average user to be changing this setting all that often anyway.

There’s no LED bling on the pump head, but the subtle design, and it’s glossy finish really does look very classy, and it goes to show that there’s more to good aesthetics that whacking a load of RGB lighting onto a product.


Priced at £109.99 in the UK at the time of this review, the Celsius S24 sits at the upper end of the cost scale for 240mm AIO coolers. For this kind of money though you are getting excellent performance, rock solid build quality with a five year warranty, and some unique features thrown in. Therefore, whilst there are cheaper alternatives on the market, I’m happy with the value for money it offers.

Final Thoughts

It’s really refreshing to a new product come onto the market, that includes new features not seen before. In the case of all-in-one CPU coolers, the basics cannot really change… but Fractal Design have managed to introduce some really nice touches with the launch of the Celsius range.

Solid build quality, excellent cooling performance, and good value for money… therefore I have no hesitation in giving the Fractal Design Celsius S24 our Play3r Gold award. Not only this, but to acknowledge the new features that Fractal have introduced with this new range, they also get the Play3r Design award.

Buy at Overclockers UK: £109.99



Huge thanks to Fractal Design for sending the Celsius S24 in for review.

  • Performance
  • Design
  • Value



– Great new innovative features
– Good cooling performance
– Solid build quality


– There are cheaper alternatives available

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