All-in-one (AIO) liquid coolers are very popular amongst advanced PC users for a variety of reasons, with a current market potential that easily rivals that of top tier air coolers. As such, nearly all of the companies involved in the production of advanced cooling products for consumer PCs are currently marketing AIO coolers. However, AIO coolers are so successful that even companies who do not currently produce any air-based cooling solutions have decided to market their own liquid-based AIO coolers.

Fractal Design, the renowned Swedish designer and manufacturer of PC cases, is one such company who has decided to offer their own AIO coolers. A couple of years ago they released the Kelvin series, a simple-looking AIO liquid cooler design, yet it was one of the few expandable kits. It also was available with a 360 mm radiator, which is very rare even nowadays.

Fractal Design just released an upgrade of the Kelvin series, the Celsius. The Celsius is based on proven hardware (i.e. Asetek parts), comes with Fractal Design’s X2 PWM fans, features interesting fan speed controls and is expandable. The new AIO cooler is available in two versions - the S24 and the S36. The only difference between these two AIO coolers is the size of the radiator that, as their names suggest, can support up to two 120 mm fans or three 120 mm fans respectively. We will examine both coolers closely in this review.

Packaging & Bundle

We received the Fractal Design Celsius coolers in large, strong cardboard packaging. The artwork on the packaging is subtle and clean, focused on pointing out the main features of the coolers. Inside the box, the coolers are well protected into a custom cardboard insert.

Both coolers share an essentially identical bundle, with the only exception being the manual. The S36 also has a few more screws for the third cooling fan. Other than that, inside each box we found the necessary CPU socket mounting hardware, screws and washers for the fans and for mounting the radiator on the case, and two cable management clips.

The fans provided with the Celsius AIO liquid cooling kits – two with the S24 and three with the S36 – are Fractal Design’s Dynamic X2 GP-12 fans. These PWM models have a very broad speed range, allowing the fans to operate anywhere between 500 and 2000 RPM. Furthermore, the serrated blades of the fans are supposed to reduce aerodynamic noise. Their engines feature a “LLS” bearing that we weren't able to find any information on – not even what the acronym stands for. A (catastrophic) disassembly of one of the fans revealed that it has what it seems to be an almost typical rifle bearing but with a magnet attached near the top. It would seem that the designer’s simple, yet effective concept was to attach a magnet at the edge of the bearing, using the magnetic force to repel the frame, reducing the friction between the stationary and rotating parts, thus significantly improving the longevity of the design. As such, the “LLS” bearing would typically classify as a “maglev” bearing engine.

The Fractal Design Celsius S24 & S36 AIO Coolers
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  • HomeworldFound - Friday, June 2, 2017 - link

    The radiators can actually support up to four to six 120mm fans. Beside that it's just another generic boring AIO.
  • sibuna - Friday, June 2, 2017 - link

    why are there no high end air coolers tested in this
  • fixxxer0 - Friday, June 2, 2017 - link

    same test setup here if you want to compare
  • Bulat Ziganshin - Monday, June 12, 2017 - link

    these are upper-middle, but not precisely high-end
  • Bulat Ziganshin - Monday, June 12, 2017 - link

    oh, well. NH-D15 is real supercooler, and its result is only a few degrees worser than results of these FD coolers (with the same noise in low speed mode)
  • Drumsticks - Friday, June 2, 2017 - link

    Thanks for the review. Could y'all do a "best CPU coolers" for the quarter and give some recommendations on each range? With Skylake X and Threadripper coming out, I think it'd be a great time to get a professional opinion. I'm kind of interested in an AIO, but there are quite a lot of choices nowadays.
  • fixxxer0 - Friday, June 2, 2017 - link

    just trying to get a feel for real world thermal loadings vs the standard shown in the test.

    how many watts would a i7 7700 stock under load generate?
  • fixxxer0 - Friday, June 2, 2017 - link

    is it really just the TDP that is advertised for the proc?
  • Drumsticks - Friday, June 2, 2017 - link

    Probably something along the lines of the 60-100 range if you aren't overclocking, but 100-200W range if you overclock depending on how far you go.
  • MrTeal - Friday, June 2, 2017 - link

    It would have been more interesting if you had run the pump at full speed and just varied the fan speed. At full speed this cooler delivered very nice acoustics for its cooling performance. It would have been nice to see how the included fans performed without kneecapping the performance of the pump.

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