Fractal Design Celsius S24 Liquid CPU Cooler Review

Performance and Conclusion

Performance Results

I tested all of the coolers in these charts using the same Intel LGA 2011 platform, with a Core i7-4820K generating the load temps for both stock results and with a 4.50 GHz overclock on all cores (at 1.30v). Ivy Bridge-E is an aging platform, but the key here is consistency of load temps across coolers, and here the Intel Core i7-4820K (130W TDP) is still capable of producing a challenging thermal load - particularly when overclocked.

First we'll take a look at temperatures with a stock CPU:

The Intel Core i7-4820K was kept very comfortable with all of the coolers in this group, and while the Celsius S24 provided good performance it was a little shy of the rest of the liquid coolers - though slightly better with my standard motherboard fan profile vs. the Auto setting (PWM passes the motherboard power managment through to the cooler). The results with an overclocked CPU would be more telling, as you will see.

The difference just grows as the load increases, with PWM mode a clear winner. Since there was a significant improvement with the Celsius S24 in PWM mode with my standard motherboard fan profile, I decided to take things one step further by running the overclocked benchmarks again with the cooler at 100% fans/pump. For this next chart I have included the first two sets of results again with the forced 100% fan and pump speeds. This new series should represent the highest performance possible with this cooler.

The difference with the fans and pump at 100% is staggering, as the Celsius S24 becomes the most effective cooler I have tested to date on this platform with overclocked loads from the i7-4820K (though admitedly I have not pushed every cooler to 100% like this). There was a big noise penalty with everything cranked up, of course, but if performance is what you're after the Celsius is certainly capable of it.

On the subject of noise levels, we will first look at the chart using the standard Auto/PWM modes of the Celsius S24:

Clearly the Auto setting favors low noise (almost inaudible in a room with a ~31.0 dBA noise floor), but the PWM results are only slightly higher as these Fractal Design fans are very quiet unless really pushed. At these standard settings the Celsius S24 is the quietest liquid cooler of this group (and one of the quietest I have ever tested, period); but how did if fare when I cranked up the speed all the way? It shot up to 43.6 dBA at 100% fans/pump, but if you are simply looking for performance that level might not be a problem (to put this in perspective it is still far lower than a reference blower cooler on a typical graphics card).

If I wanted to push my CPU to its limit I would simply disable power management for the CPU fan header and run the Celsius at 100% via the PWM setting, though I would devote more time to finding a happy medium between performance and noise by further adjusting speeds.

Conclusion

Out of the box Fractal Design's Celsius S24 is a well built, extremely quiet liquid CPU cooler that offers pretty good performance. While the Auto setting suffered under heavy loads, simply controlling the CPU fan profile manually (with the PWM pass-through setting) allows performance to be increased significantly, while tailoring the fan speeds to individual noise preferences. If you are willing to play around with fan profiles a bit with your motherboard I highly recommend using the S24 cooler that way, as it was not a great performer for a 240 mm AiO cooler with the Auto setting.

Overall I was pretty impressed with this new Celsius S24 cooler - when I was controlling speeds myself (though noise increases along with performance). It features Fractal Design's typically premium fans and is very easy to install, but I would have liked to see a slightly higher performing Auto setting from the Celsius. This default option does at least provide a quick solution for getting an extremely quiet experience, however. In fact, 'Auto' could just be labeled 'Silent' and I would be satisfied.

With solid construction, very quiet operation, and the potential for very high performance after some quick fan speed adjustments, the Fractal Design Celsius S24 is a flexible option in the crowded all-in-one CPU cooler space.