ZEROtherm CoolMaxx 4000 VGA Cooler Review

Many graphics card owners dream about a compact, lightweight cooler that would only block one PCI slot on their mainboard. And ZEROtherm Company is ready to offer them one. Our today’s article will help you learn how efficient and nosy the new VGA cooler from ZEROtherm is.

by Sergey Lepilov
08/16/2011 | 11:13 AM

Almost all alternative coolers for graphics cards have one common drawback: they block at least one and in most cases – two PCI slots on the mainboard. At the same time, it is better to keep the third PC slot empty in order to ensure that there is proper airflow coming to the cooler fans. This way, you improve the graphics card cooling and lower the level of noise by losing two or even three PCI slots on your mainboard. As a result, very often the users have to give up the idea of replacing their reference VGA cooler with a more efficient and quieter alternative. The South Korean ZEROtherm Company decided to solve this issue once and for all and launched a new graphics card cooler called CoolMaxx 4000.


I have to say, though, that the new cooler is not really universal and has a number of compatibility restrictions. But, we will dwell on them a little later today, and in the meanwhile let’s meet the new ZEROtherm CoolMaxx 4000!

Packaging and Accessories

The box is made of thick glossy cardboard. It is very bright and has ton of color in its design:


The key features of the cooler are marked with individual icons on the front of the package. There is also a photograph of the cooler and a list of compatible graphics accelerators. The back of the box offers technical specifications of the cooler, its dimensions and a list of included accessories.

ZEROtherm CoolMaxx 4000 is bundled with the following items:

The cooler is made in South Korea. Its MSRP is set at $54.90.

Design and Functionality

The first impression from the ZEROtherm CoolMaxx 4000 is that this cooler is fairly small. It is only 165 mm long, 95.4 mm wide and 31 mm thick. It looks very compact and neat:

CoolMaxx 4000 weighs 235 grams and features very simple structure. Copper heatpipes 6 mm in diameter come out of the copper base plate and hold aluminum heatsink plates, with two fans pushed inside the heatsink. That is why when you look at the cooler from the front, it may seem at first that it is a passive (fanless) cooling system.

The sides of the heatsink are covered by the plate edges bent downwards:


The entire heatsink is nickel-plated and looks very finished and stylish.

ZEROtherm has a name for their innovative design when the fans are “hidden” inside the heatsink body. They call it “Stealth Design”. The cooler does actually look very unusual:


The heatsink consists of 52 aluminum 0.3 mm plates with 1 mm gaps between them. Since the heatsink is pretty small and has fans inside, the plates are quite narrow and create small overall effective surface of less than 1000 cm2. In fact, this number is so small that the concerns about the cooling efficiency of this product become totally justified…

It is hard to tell how the heatsink plates are attached to the heatpipes and the heatpipes to the base, because we didn’t see any traces of soldering or thermal glue in any of the contact spots. Nevertheless, the heatsink is put together very solidly and the plates do not wobble even a bit.

There are three heatpipes in this cooler. Once of them actually pierces the base plate twice, so you may get the impression that there are, in fact, four of them.


Each heatpipe lies inside a groove and the thinnest part of the cooler base plate measures 2 mm.

The copper surface of the 50x50 mm base is finished very nicely, even though we can see some texture on it:

In reality the base surface is very smooth and you can’t feel the marks to the touch at all. However, the evenness of the base is seriously flawed. In fact, the base is not just uneven, but has a few different uneven spots. For example, here is the thermal paste imprint left by the GPU heat-spreader on Leadtek GeForce GTX 560 card:


And here is one from Inno3D GeForce GTX 560 Ti:

Note that the heat-spreaders of both these GPUs are even and produced perfect imprints on their original coolers (you are going to see them in our next article). The only card that gave us a good thermal paste imprint was AMD Radeon HD 6870:

However, ZEROtherm CoolMaxx 4000 didn’t do anything for this particular card. We are going to explain why a little later.

ZEROtherm CoolMaxx 4000 cooler comes with two 80x15 mm fans from PowerLogic:

PLA08015S12H fan model is based on the best UFO slide bearing. The fans rotation speed can be adjusted automatically using PWM method between 1300 and 2700 RPM generating 20-33 dBA of noise. The static pressure and airflow aren’t mentioned in the official technical specifications. The maximum power consumption for each fan shouldn’t exceed 2 W. the cooler comes with an adapter cable for the three-pin mainboard connector, if the standard four-pin connector turns out incompatible with your graphics card.

In conclusion I have to add that the fans feature red LEDs:

The LEDs cannot be turned off, and their brightness varies depending on the fan rotation speeds.

Compatibility and Installation

Considering the size of ZEROtherm CoolMaxx 4000 and its small effective heatsink surface, we assume that this cooler can only work find with not very hot graphics accelerators. And ZEROtherm does understand that well enough, as they market it for Nvidia GeForce GTS 450 and GTX 460. Nevertheless, the cooler may theoretically be compatible with all graphics accelerators, which have a diagonal distance of 75.4 mm and 79.4 mm between the retention holes:

Among them are quite a few graphics accelerators including those on AMD GPUs, too. For example, Radeon HD 6850 and Radeon HD 6870 also fit this profile, but the question is: will the cooling efficiency of the small ZEROtherm CoolMaxx 4000 be sufficient to handle them well?

ZEROtherm CoolMaxx 4000 installation is very simple and looks as follows:

We are going to explain it step-by-step using Gigabyte GeForce GTX 560 1 GB Ultra Durable (GV-N56GOC-1GI) graphics card as an example.

First we have to remove the default graphics card cooler, stick the heatsinks onto the memory chips and apply a new layer of thermal paste onto the GPU previously wiped clean. After that we have to get ZEROtherm CoolMaxx 4000 ready for installation by inserting threaded mounts into the holes in its retention brackets:

Then we have to put the cooler onto the graphics card and tighten the spring-screws with plastic washers on the back of the card:

The next step is to connect the power cable to the graphics card (or to the mainboard via the included adapter) and that’s it:

Quick and easy. This is what ZEROtherm CoolMaxx 4000 looks like installed onto the above mentioned AMD Radeon HD 6870:

It seemed to fit perfectly and to have proper retention pressure, but unfortunately, one of the fans wouldn’t rotate because it was blocked by the graphics card capacitors:

The same thing happened with AMD Radeon HD 6850, and of course, it simply doesn’t make sense to use this compact cooler with powerful Radeon HD 6950 and HD 6970. Especially, since there are no VRM heatsinks included with the cooler anyway.

The new cooler fit best of all onto Inno3D GeForce GTX 560 Ti, where there were no conflicts with any of the graphics card electronic components and there was a special additional cooling plate used for them:

However, we can’t expect this cooling combo to work too well, because of the extremely uneven base, which we have just described above.

Technical Specifications and Recommended Pricing

Testbed and Methods

The tests were performed in a closed system case. Our testbed was configured as follows:

Since we couldn’t get the new ZEROtherm CoolMaxx 4000 cooler to work on any of the AMD Radeon HD graphics cards that we had at the time of tests, we only checked its performance on Nvidia GeForce GTX. Unfortunately, both graphics cards use their own proprietary coolers, which are more efficient than the reference to begin with:



That is why we can only compare the performance of the CoolMaxx 4000 with the performance of these two coolers. Well, looks like ZEROtherm’s challenge just got harder :)

The testing programs were installed under Microsoft Windows 7 Ultimate x64 SP1. We used DirectX End-User Runtimes libraries (from November 2010), Nvidia GeForce/ION 280.25 graphics card drivers. We used two 12-minute runs of FurMark version 1.9.1 in stability test mode with “Burn-in” option enabled and resolution set to 1920x1080 resolution. We enabled anisotropic filtering 16x in the driver control panel in order to increase the GPU operational load:

We also measured the graphics card temperatures in game mode using five runs of Aliens vs. Predator game in 1920x1080 resolution with maximum graphics quality settings but without antialiasing:

By testing the graphics cards in this mode we should be able to see their temperatures under typical gaming load.

We used MSI Afterburner utility version 2.2.0 Beta 5 to monitor graphics card temperatures and frequencies and GPU-Z version 0.5.4 utility:

The tests were run at least twice for each type of load. The temperature stabilization period between the two test cycles was about 10-12 minutes. The ambient temperature was checked next to the system case with an electronic thermometer with 0.1°C precision that allows monitoring the temperature changes over the past 6 hours. During our test session room temperature stayed around 25.0-25.8°C.


Despite the improper contact between the ZEROtherm cooler and the GPU heat-spreaders on both tested graphics cards as seen from the horrific thermal paste imprints, CoolMaxx 4000 did a good job cooling Gigabyte GeForce GTX 560 even in FurMark, while the original cooler of this graphics card is unable to handle FurMark load:

In this respect we are mostly interested not really in the difference in cooling efficiency, but rather in the mere fact that ZEROtherm CoolMaxx 4000 can, in fact, cool a graphics card with an uneven base surface like that. Moreover, ZEROtherm cooler not only successfully competed against the original Gigabyte cooler, but also ensured stable graphics card operation in FurMark, which loads the cards very heavily, so that the cards may even stop working at all.

As for the CoolMaxx 4000 performance with an overclocked GeForce GTX 560 Ti, here ZEROtherm’s performance was significantly more modest. In fact, the cooler passed the test with an overclocked graphics card only when both of its fans rotated at their maximum speed and only in the gaming mode:

ZEROtherm CoolMaxx 4000
(2710 RPM x2)

Inno3D iChiLL
(1500 RPM x2)

Inno3D iChiLL (3400 RPM x2)

In this case the GPU temperature reached 81°C, so it didn’t make much sense to launch FurMark after that, as the outcome was quite predictable. I also have to add that the original cooler of the Inno3D iChiLL GTX 560 Ti graphics card turned out 7°C more efficient than ZEROtherm CoolMaxx 4000 at quiet 1500 RPM and as much as 16°C more efficient at maximum 3400 RPM. We are going to talk more about it in our next review.

As for the acoustic performance of the new ZEROtherm CoolMaxx 4000, we can say that we could hear this cooler at about 1700 RPM against the background of our fairly quiet system, but up until 2000-2100 RPM the noise remains within the acoustic comfort zone. I doubt that anyone will ever use it at maximum 2700 RPM fan speed, because the noise in this case is pretty loud. At the same time, both of its 80 mm fans didn’t produce any parasitic noises during work, and the heatsink plates didn’t generate any jingling sounds.


Our today’s review of the new ZEROtherm CoolMaxx 4000 VGA cooler left very ambiguous impressions. On the one hand, the results obtained with GeForce GTX 560 indicate clearly that the cooler will cope perfectly fine with GeForce GTS 450 and GTX 460, as promised in the specifications. Especially, since it cooled more powerful graphics accelerators with its uneven base without rally breaking a sweat. Moreover, the new cooler is very compact, easy to install and has bright fan LEDs, which will please modding fans for sure.

But on the other hand, we saw some very obvious quality issues in this ZEROtherm product and its compatibility with AMD Radeon HD 6870 and HD 6850 graphics cards, which could use a cooler like that. Another drawback is the lack of a VRM heatsink among the bundled accessories. But the most unexpected thing is definitely the MSRP of CoolMaxx 4000 set at $54.90. In our opinion, a cooler of this size and such small list of compatible products shouldn’t be priced at more than $30. At this time, however, ZEROtherm CoolMaxx 4000 will have really hard time finding its customers.