The Fractal Design Celsius S24 & S36 AIO Coolers Review
by E. Fylladitakis on June 2, 2017 8:00 AM ESTTesting Results, Low Fan Speed
Before dissecting our low fan speed results, we should begin by noting that the design of the Celsius AIO coolers suggests that the fans will be powered by the cooler itself, from the hub on the radiator. With the whole assembly powered by a single cable, applying any fan speed control to the cooler will also affect the liquid pump as well. This particular pump does not react properly to a reduced voltage input, essentially requiring PWM control. Using a PWM voltage regulator, we reduced the speed of both kits down to their minimum operating point, which brought the speed of the fans down to 550-560 RPM.
The thermal performance of the Celsius kits with their fans and pumps driven down to minimum speed produced some very interesting results. Individually, the Celsius S24 displayed comparatively good thermal performance in conjunction with exceptionally low noise levels. The average thermal resistance of 0.1154 °C/W is mediocre when compared to that of other similarly sized coolers, but the sound pressure reading of 32.1 dB(A) is the lowest that we have recorded up to this date. Other recently released products could possibly rival the acoustics performance of the Celsius S24 if both the fans and the pump were driven via PWM controllers, but the Celsius series offers the convenience of concurrently driving everything via a single PWM signal/cable.
| Core Temperature, Constant Thermal Load (Low Fan Speed) |
However, the reduction of the pump’s speed alongside with the fans does not work as well for the larger version of the Celsius. The Celsius S36 not only did not perform significantly better than the S24 during this test, but it actually performed worse, especially at low load levels. Our assumption is that the small ceramic pump is not powerful enough to have its speed reduced that much and still be able to cope with the resistance of such a large radiator, meaning that the liquid flow was lowered to the point that outweighed the benefit of the greater heat exchange area. Regardless of equipment, measuring the flow without interfering with the factory configuration was all but impossible, so we cannot currently put our theory to the test. Nonetheless, irrespectively of the correct answer, the fact is that the Celsius S24 performs better than the large S36 with the speed of the pump and fans down to their minimum setting.
Facebook
Twitter
RSS
31 Comments
View All Comments
dave_the_nerd - Friday, June 2, 2017 - link
So when do they sell one of these bundled with a Node 804?Akkuma - Friday, June 2, 2017 - link
The Arctic Liquid Freezer 240 & 120 seem to be the current bar for AIO. The price is better, the performance is better, and the sound profile seems better.jabber - Sunday, June 4, 2017 - link
Yeah I have the Arctic 240 and its great. Lot of kit for the money. One of the best around. I had put my old Corsair H50 in to try cooling my new 5820k rig but it just didnt have enough cooling power for that. Would have been nice to have had the Fractal option this time last year though to put in my new Fractal case...CompLuva - Friday, June 2, 2017 - link
I just got the s24 and my experience so far is that when the fans are at 100%, it's very loud. I can't compare to other AIOs since this is my first, but my old system which used a 120mm NFP12 Noctua was virtually silent at 100%. I know that's not exactly apples to apples, but still this thing is quite loud when at 100%. It also spins up and down a lot and the noise when doing that is pretty loud and noticeable too. The other issue with it is that since it uses it's own fan controller, I can't tell if the readout I'm getting in BIOS is for the pump speed or fan speed. I think it's for the pump since it'll read out 2800 and the fans are only 2000 rpms.CompLuva - Friday, June 2, 2017 - link
I retract my comment about the noise. I changed the positioning of the fans and radiator and it's much quieter now. I had the fans mounted to the case and then attached to the radiator. Turns out that small amount of space from the case mounting was causing a bunch of noise. Now I mounted the fans directly on the radiator and it's super quiet even at 100%. Very happy now. I've running 7700k @ 4.8 and 1.3v and max out at around 68-70 degrees when stress testing.Still can't see the fan speed though due to the integrated fan controller.
*zSnowz* - Friday, June 2, 2017 - link
How reliable are these AIO coolers? I worry about leakage. How often do AIOs leak?maximumGPU - Saturday, June 3, 2017 - link
it's *very* rare. Quality has gone up a lot in the past few years.verl - Saturday, June 3, 2017 - link
The biggest worry for an AIO is how long the pump will last for. I think most ppl hit the 3-4 year range.Makaveli - Saturday, June 3, 2017 - link
^^^^ ThisThe H55 on my 7970ghz has been there for about 4 years now and the pump is alot noiser now than it use to be so it will almost be time to replace it.
nekronimus - Wednesday, October 18, 2017 - link
There's a 5 year warranty on the S24/S36 as a whole. If you modify the loop i.e. detach any hose, you "only" have warranty on the individual parts. That's logical 'cause if say you drain and refill it and it performs bad it means you did a bad job at refilling, fractal can not held accountable for that.