Original Link: http://www.anandtech.com/show/8280/zalman-reserator-3-max-dual-cpu-cooler-review



Introduction

A few months ago, we had a look at many all-in-one liquid cooling solutions, ranging from low cost solutions to enthusiast-grade products. However, regardless of their size and capabilities, all of those kits were quite similar to each other. Today we have something that truly stands out from the crowd, Zalman's latest liquid-cooling solution, the Reserator 3 Max Dual.

Zalman's engineers are no amateurs when it comes to liquid cooling; they actually are one of the first companies that shipped liquid cooling solutions as complete retail products, so they have extensive experience in that particular field. The Reserator 3 Max Dual is being advertised as the "Ultimate Liquid CPU Cooler" and it currently retails for $140 including shipping, making it one of the most expensive all-in-one solutions available. It's clearly aimed at overclockers and enthusiasts, but is Zalman's newest creation worthy of such a heavy title and premium price? We will find out in this review.

Packaging and bundle

We received the Reserator 3 Max Dual in a large, dark cardboard box with little aesthetic appeal, as the artwork is based on a picture of the radiator. Blister plastic packaging protects the cooler inside the box. The bundled items are supplied into two plastic bags, entirely unorganized. Besides the hardware required for the mounting of the cooler and the instruction manuals, Zalman does not provide anything else. The thermal paste is the weak link of the bundle, as only a single dose of average thermal paste is supplied, when most users would expect at least a small syringe with high-quality thermal paste with such a premium product.



The Reserator 3 Max Dual AIO CPU Cooler

In terms of design, the Reserator 3 Max Dual certainly stands out from the crowd. Zalman ditched the classic two-pass radiator for a unique tube-based design, which appears to be based on the style of their "flower-type" air coolers. It is an all-copper design, with the tube making multiple passes across each fin array. The copper makes the Reserator 3 Max Dual a heavy construct, tipping our scales at 1470 gr, increasing the overall weight of a system by quite a bit.

In order to prevent corrosion, Zalman chromed all of the metallic parts. A semi-transparent plastic frame protects the metallic parts and holds the two 120 mm fans. The company and product logos can be seen at the sides of the assembly, but they are printed upside down for some peculiar reason.

Another unique characteristic of this design is that the entry and exit points are at the middle of the assembly. Overall, it is a very nice looking but also very thick assembly; with a height of 74 mm, it is the thickest all-in-one cooler radiator that we have tested to this date. For this purpose, Zalman includes installation brackets that will help the cooler to clear the motherboard and RAM modules by creating an offset, assuming that your case is wide enough as well.

The circular block assembly sports an elegant, attractive design based on geometric shapes and metallic colors. It has a very well made copper base, free of imperfections. The pump is powered via a typical 3-pin header, as if it was a CPU cooler fan. When powered, a blue LED ring lights up at the top of the block assembly, creating a nice visual effect.

The two cooling fans also feature LED lighting, but they do not have the usual side-firing LEDs, with the soft lighting coming from the center of the fan. Both fans are PWM-controlled and can be powered from a single 4-pin motherboard header. They have a theoretical maximum speed of 2300 RPM and a "long life bearing", for which we could not find detailed information, but it appears to be a form of a fluid dynamic bearing.



Testing Methodology

Although the testing of a cooler appears to be a simple task, there are many factors that need to be considered. 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. However, extracting the absolute thermal resistance of a cooler is no simple task.

The thermal load has to be perfectly even, steady and controllable. The latter is critical as thermal resistance 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 in the thermal load can yield very different results.

Appropriate thermal testing requires the creation of a proper testing station and the use of laboratory-grade equipment. To accomplis this, 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 manual control of the testing equipment, the acquisition of the ambient temperature, and the in-core temperatures via PT100 sensors. It also handles the logging of the test results and the mathematical extraction of performance figures.

Finally, as noise measurements are a bit tricky, their measurement is only performed manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is acquired via a laser tachometer. The fans (and pumps, when applicable) are powered via an adjustable, fanless desktop DC power supply and noise measurements are taken 1 meter away from the cooler, in a straight line from the 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.

<35dB(A) Virtually inaudible
35-38dB(A) Very quiet (whisper)
38-40dB(A) Quiet (slight humming)
40-44dB(A) Normal (humming noise, comfortable level)
44-47dB(A) Loud* (strong aerodynamic noise)
47-50dB(A) Very loud (strong whining noise)
50-54dB(A) Extremely loud (About equivalent to a typical hairdryer)
>54dB(A) Intolerable for home/office use, special applications only.

*noise levels above this are not suggested for daily use



Testing Results, Maximum Fan Speed (12 Volts)

The first round of testing takes place with the supply voltage of the fans and pumps at 12V. This should depict the maximum possible performance of each cooler without any modifications.

Fan Speed (12 Volts)

Noise level

Core temperature (60 W Load)

Core Temperature, Constant Thermal Load

Average thermal resistance, 60 W to 340 W

From the above charts, we can see that the Reserator 3 Max Dual has different behavior than many of the other coolers. Zalman's cooler behaves extremely well when the load is low, easily claiming the top spot of our thermal performance charts and outperforming even the larger 280 mm radiator designs. However, the performance of the Reserator 3 Max Dual decreases as the load increases and it can't really keep up with the competition at very high loads. The end result is a middling, unsurprising average thermal resistance. The sound pressure of Zalman's 120 mm LED fans at maximum speed is an ear-bursting 51.5 dB(A) as well, though that's no surprise considering the specifications.



Testing Results, Low Fan Speed (7 Volts)

The second round of testing takes place with the supply voltage of the fans and the pump at 7V. Although certain fan models and pumps can work at lower voltages as well, we consider 7V to be the threshold of maximum compatibility (i.e. all fans and pumps should operate seamlessly with this voltage, and all fan controllers/motherboards should be able to supply it).

Fan Speed (7 Volts)

Noise level

Core temperature (60 W Load)

Core Temperature, Constant Thermal Load

Average thermal resistance, 60 W to 340 W

After dropping the voltage of the fans down to 7V, the characteristic performance of the Reserator 3 Max Dual remains unchanged, with the cooler delivering outstanding performance at low loads and, once again, the thermal resistance decreases as the load increases.

With their supply voltage decreased to 7V, the fans are still audible but generating just 37.4 dB(A), a fairly comfortable figure. Remember that the fans are PWM controlled and their speed may decrease even further if they are powered from your motherboard's CPU fan header, as long as the temperature of the CPU and the user settings allow it.



Conclusion

The Reserator 3 Max Dual is Zalman's trump card in the field of all-in-one liquid coolers and currently the most advanced such cooler that they offer. After they discontinued the Reserator 1 V2, it also is their most expensive liquid cooler, currently retailing for $140 incl. shipping at the time of this review. With the exception of the Enermax kits, which are unavailable in the US and importing them raises their cost dramatically, this makes the Reserator 3 Max Dual the most expensive all-in-one liquid cooler that we have tested to this date, regardless of size and features.

Zalman's Reserator 3 Max Dual certainly has a very long list of positive aspects. To begin with, it sports an impressive appearance that will easily stand out, without being extravagant or overly aggressive. It is very well made, using high quality materials and is free of imperfections. The PWM controlled fans are very handy to have, as their speed can be controlled by the motherboard, essentially emulating a typical CPU cooler and eliminating the need for external speed controllers and unnecessary cable clutter. If quality and appearance are what drives you, the Reserator 3 Max Dual will not be a disappointment.

On the other hand, the Reserator 3 Max Dual is far from flawless. The fancy-looking radiator is bulky and may easily create compatibility problems. Even with the supplied offset installation brackets, the case needs to be wide enough and you might lose a small portion of the radiator's area if the case does not have 140 mm fan openings. Moreover, although it sounds silly and unimportant, the decals on the sides of the radiator are upside down and that will look bad from a windowed side panel of a well-designed system. (Hopefully this is something that Zalman has fixed in their assembly process.) But ultimately, it's the performance of the Reserator 3 Max Dual cooler that confounds us the most.

Every all-in-one cooler that we have ever tested has a thermal resistance that either remains nearly constant or improves slightly as the load increases. Ideally, the thermal resistance of the cooler should be constant, but there are many factors at play in a complex multi-liquid system such as this. However, the thermal resistance of the Reserator 3 Max Dual increases alongside the load, which is inexplicable with what we know about this cooler.

Copper tends to have a thermal conductance that decreases faster than that of aluminum as the temperature rises, but the temperatures that we deal with are low and the change seems rather abrupt, therefore this is not very likely. Although we cannot fully explain why, it seems that the Reserator 3 Max Dual cannot dissipate high quantities of thermal energy quickly enough. This makes it the perfect cooler for the newest generation of processors but, at the same time, a bad idea for anyone who plans to use an energy-hungry CPU (e.g. extreme overclocking).

Our expectations were much higher from a product that is being advertised as the "ultimate CPU cooler". Assuming that the majority of enthusiasts that will buy such a cooling solution will also overclock their systems, we can only recommend the Reserator 3 Max Dual to those that will be using Haswell core processors, as they have very low energy requirements. If you expect the thermal power of your CPU to exceed 120 Watts when stressed, then another product will most likely be both cheaper and more effective.

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