Enthusiasts and other advanced PC builders seldom embrace the use of a stock cooling solution. Stock coolers are adequate for their intended purpose but often end up delivering mediocre acoustic performance, and they cannot handle the thermal loads of a gaming and/or overclocked system. As a result, what has been a rule since the first actively-cooled x86 processors hit the market almost 30 years ago remains a rule today: most enthusiast builds are made using aftermarket coolers. All of which has led to (and continues to sustain) the massive market for coolers and other PC peripherals.

In today's review, we are having a look at the IceSLEET G6 Stealth tower cooler by Iceberg Thermal. Iceberg Thermal is a relatively new player in the PC market, with the company founded in Tempe, Arizona, in 2019. Regardless, the company’s employees and engineers have many years of experience in the design and marketing of cooling products.

The IceSLEET G6 Stealth is, as hinted by its name, a cooler primarily designed around minimal noise output. Most of the company’s marketing efforts are also focused on how quiet the cooler is. Meanwhile, a quick glance at the specifications reveals that this is also a behemoth of a cooler, measuring 160 mm tall and wide, and weighting over 1 kg. With that much mass and considering its $80 price, Iceberg Thermal is definitely aiming for the top performance spots of the air-based CPU cooling market.

Packaging & Bundle

Iceberg Thermal supplies the IceSLEET G6 Stealth in an inconspicuous box, with the artwork printed directly onto the brown cardboard walls. Basic information about the cooler is printed on the rear side of the box. It is aesthetically pleasing and at least partially ecological but, above all else, the box is strong and the cooler is tightly packed inside, ensuring safe shipping.

Inside the box, we only found the parts that are necessary for the installation of the cooler. Everything is very neatly packed and labeled, which should prevent any confusion during installation. All of the metal parts are plated, creating a titanium-like appearance and protecting them from corrosion in the long run. Iceberg Thermal includes a syringe of thermal compound, enough for at least three applications.

The Iceberg Thermal IceSLEET G6 Stealth CPU Cooler

The IceSLEET G6 Stealth is a slightly unorthodox tower cooler, designed to engulf the 140 mm fan entirely within its fins. There are six copper heatpipes transferring the thermal energy from the tiny base to the fin array. The cooler is 160 mm (6.3”) tall, pushing the limit of standard ATX cases.

A close inspection of the fins reveals an uneven, abstract design. Manufacturers frequently implement different fin profiles in order to improve the overall performance characteristics of the cooler, yet the fins usually are uniform. The fins of the IceSLEET G6 Stealth form a total of six groups, with each group having nine identical fins. The lowermost group is a little smaller, allowing for a 56 mm RAM clearance. Above that first group, there are two distinct groups of nine fins each that alternate.

A plastic black/turquoise cap covers the top of the cooler, concealing the heatpipe ends and the cooling fan. The cap is held into place via four screws.

The top cap also serves as a support for the 140 mm cooling fan. It clips on the two top screw holes of the large fan, firmly holding it and concurrently operating as a passive shock absorber, reducing vibration-related noise.

The 140 mm fan hidden inside the humongous metal body of the cooler is rebranded by the company and we could not recognize who the OEM behind its creation is. We did find out that it has a fluid dynamic bearing (FDB) engine, an advanced sleeve bearing design with a significantly boosted lifetime. It can reach up to 1400 RPM, which is a very high speed for a large 140 mm fan.

All of the cooler’s metallic parts, including the heatpipes and the base, have been treated with a gunmetal grey plating. The plating is more than an aesthetic upgrade as it will protect the cooler from corrosion and oxidation in the long run.

The IceSLEET G6 Stealth has a very tiny base, disproportionately small for the size of the gigantic cooler. A small aluminum block serves both as the foundation of the steel brace that is used to mount the cooler and as the mechanical support for the copper heatpipes. It is the six heatpipes, and only the heatpipes, that come in direct contact with the CPU.

Testing Methodology

Although the testing of a cooler appears to be a simple task, that could not be much further from the truth. Proper thermal testing cannot be performed with a cooler mounted on a single chip, for multiple reasons. Some of these reasons include the instability of the thermal load and the inability to fully control and or monitor it, as well as the inaccuracy of the chip-integrated sensors. It is also impossible to compare results taken on different chips, let alone entirely different systems, which is a great problem when testing computer coolers, as the hardware changes every several months. Finally, testing a cooler on a typical system prevents the tester from assessing the most vital characteristic of a cooler, its absolute thermal resistance.

The absolute thermal resistance defines the absolute performance of a heatsink by indicating the temperature rise per unit of power, in our case in degrees Celsius per Watt (°C/W). In layman's terms, if the thermal resistance of a heatsink is known, the user can assess the highest possible temperature rise of a chip over ambient by simply multiplying the maximum thermal design power (TDP) rating of the chip with it. Extracting the absolute thermal resistance of a cooler however is no simple task, as the load has to be perfectly even, steady and variable, as the thermal resistance also varies depending on the magnitude of the thermal load. Therefore, even if it would be possible to assess the thermal resistance of a cooler while it is mounted on a working chip, it would not suffice, as a large change of the thermal load can yield much different results.

Appropriate thermal testing requires the creation of a proper testing station and the use of laboratory-grade equipment. Therefore, we created a thermal testing platform with a fully controllable thermal energy source that may be used to test any kind of cooler, regardless of its design and or compatibility. The thermal cartridge inside the core of our testing station can have its power adjusted between 60 W and 340 W, in 2 W increments (and it never throttles). Furthermore, monitoring and logging of the testing process via software minimizes the possibility of human errors during testing. A multifunction data acquisition module (DAQ) is responsible for the automatic or the manual control of the testing equipment, the acquisition of the ambient and the in-core temperatures via PT100 sensors, the logging of the test results and the mathematical extraction of performance figures.

Finally, as noise measurements are a bit tricky, their measurement is being performed manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is being recorded via a laser tachometer. The fans (and pumps, when applicable) are being powered via an adjustable, fanless desktop DC power supply and noise measurements are being taken 1 meter away from the cooler, in a straight line ahead from its fan engine. At this point we should also note that the Decibel scale is logarithmic, which means that roughly every 3 dB(A) the sound pressure doubles. Therefore, the difference of sound pressure between 30 dB(A) and 60 dB(A) is not "twice as much" but nearly a thousand times greater. The table below should help you cross-reference our test results with real-life situations.

The noise floor of our recording equipment is 30.2-30.4 dB(A), which represents a medium-sized room without any active noise sources. All of our acoustic testing takes place during night hours, minimizing the possibility of external disruptions.

*noise levels above this are not suggested for daily use

Testing Results, Maximum Fan Speed

To begin with, we are having a look at the IceSLEET G6 Stealth with its stock 140 mm fan running at its maximum speed.

Due to its enormous mass, we expected the IceSLEET G6 Stealth to land near other similarly-sized products, such as the Noctua NH-D15 and the Phanteks PH-TC14PE. We were not mistaken, as the average thermal resistance of 0.099 °C/W is extremely close to the figures we received from those other coolers.

The IceSLEET G6 Stealth seems to have trouble coping with very low loads, as the thermal resistance is unnaturally high in those scenarios, hinting that the energy transfer is rather slow. As the load increases and the temperature gap between the cooler and the cooling medium (air) widens, the thermal resistance drops considerably.

The IceSLEET G6 Stealth is, as its name also suggests, a product designed with acoustics in mind. Its 140 mm fan spins at exactly 1400 RPM and makes a rather good job of keeping noise levels relatively low. The cooler is clearly audible with the fan running at maximum speed but even then the noise pressure figures are tolerable for typical stress usage scenarios.

Testing Results, Low Fan Speed

Switching things up a bit, let's next take a look at cooler performance with the Iceberg Thermal 140 mm fan taken down to half speed.

After reducing the speed of the fan to about 700 RPM, the thermal performance of the IceSLEET G6 Stealth degraded only slightly, as expected from a cooler with so much mass and surface area. Once again, the thermal performance of the IceSLEET G6 Stealth is on par with that of other similarly sized coolers. It also follows the same pattern, with mediocre thermal resistance at very low loads and exceptional figures when the load is very high.

Dropping the speed of the Iceberg Thermal 140 mm fan down to 720 RPM makes the IceSLEET G6 Stealth cooler practically inaudible. With no direct line of sight, it is impossible to discern whether the fan is spinning or not even if very close to the cooler. It would take a very quiet room and very close proximity to hear the fan under such conditions.

Thermal Resistance VS Sound Pressure Level

During our thermal resistance vs. sound pressure level test, we maintain a steady 100W thermal load and assess the overall performance of the coolers by taking multiple temperature and sound pressure level readings within the operating range of the stock cooling fans. The result is a graph that depicts the absolute thermal resistance of the cooler in comparison to the noise generated. For both the sound pressure level and absolute thermal resistance readings, lower figures are better.

This chart reveals where the IceSLEET G6 Stealth lands at compared to its major competitors. We can see that practically only the Noctua NH-D15 slightly outperforms the Iceberg Thermal cooler, with every other cooler matching the same thermal performance at higher sound pressure levels.

Conclusion

Iceberg Thermal is a newly founded and by all means small company, with only a few CPU coolers and closely related products summing up its entire product lineup. There have been many similar startups that came and went over the past couple of decades, with but a small percentage actually succeeding and staying in business. With the IceSLEET G6 Stealth, Iceberg Thermal is boldly challenging the top players of the PC cooling market, trying to establish a reputation with enthusiasts and other performance users.

The quality of the IceSLEET G6 Stealth is impeccable. No matter how closely one examines the cooler, there is not a single weak point, a bent fin, or a flaw on the plating. The mechanical strength of the cooler is excellent and, in combination with the plating, it ensures that the cooler will be unscathed by the passage of time and multiple installations/removals. It would be extremely difficult to mechanically damage this cooler – only the fan may fail after several years of use but any quality 140 mm fan can easily replace it if that happens.

When it comes to performance, the IceSLEET G6 Stealth does not disappoint either. The company’s marketing efforts are not hollow, as the cooler’s noise figures are exceptionally low. Under normal operating circumstances, the IceSLEET G6 Stealth should be practically inaudible, even with the system under load if it is called to cool a mainstream CPU operating at stock frequency. The design and colossal proportions of the cooler allow for the handling of extreme thermal loads with relatively little airflow, placing the IceSLEET G6 Stealth among the first slots of our performance charts.

The Iceberg Thermal IceSLEET G6 Stealth is a strong contender for one of the best CPU air coolers ever made. Nevertheless, it is not without flaws. The massive size of the cooler necessitates a very roomy case and we're concerned that its hefty weight could easily cause damage to the motherboard if the case is to be transported. Its size also means it will almost certainly cover some of the RAM slots – the clearance of 56 mm will allow for some RAM modules to fit but there still is some compatibility risk with high-performance RAM modules, plus it will prevent the installation/removal of the RAM modules while the cooler itself is installed. Such flaws are not unforeseen for any tower cooler that large and are relatively minor for most system builders, but these are factors that need to be assessed nonetheless. Otherwise, the retail price of $80 is a bit steep but we believe it to be fair considering the quality, performance, and sheer mass of the cooler.

In summary, the IceSLEET G6 Stealth is an excellent top-tier air cooler, designed for top-of-the-line thermal and acoustics performance. For a product from a small company that's still working to make its name in the packed cooling industry, Iceberg's towering cooler makes a very big and very good impression.