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ZEROtherm CoolMaxx 2000 GPU Cooler

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The ZEROtherm CoolMaxx 2000 is a deceptively small and light GPU cooler with high aspirations to match its $55 price-tag. To test its mettle, we put it through the grueling challenge of cooling a 150W Radeon HD4890 in an limited airflow environment.

November 30, 2009 by Lawrence Lee

Product ZEROtherm CoolMaxx 2000
GPU Cooler
Manufacturer ZEROtherm
Street Price ~US$55

ZEROtherm, the makers of the Core92 and
Nirvana CPU coolers,
have produced an interesting GPU heatsink, dubbed the CoolMaxx 2000. With a
street price of $55, you may expect a high-end cooler with a couple more heatpipes
than usual and/or a monstrous heat dissipation area, but you’d be mistaken.
Like most modern video card heatsinks, it sports a basic structure of 4 heatpipes
extending over the GPU core with fins running parallel to the circuit board,
and actually its overall dimensions are less than impressive. The CoolMaxx is
only 6.7″ long and weighs in at just 230 grams according to our digital

The CoolMaxx 2000.

Graphics card compatibility.

The CoolMaxx resembles the Zalman
, though the fins are composed of aluminum rather than copper,
and the fan happens to sit underneath, rather than over the top or embedded
within the main fin mass. Instead of trying to dissipate heat from the heatsink
body, the fan is designed primarily to blow down directly on the base to take
care of the problem at the source. Unfortunately, the position and size of the
fan will undoubtedly make for poor VRM cooling, which some high-end cards desperately
need. As such, the list of compatible graphics cards is not extensive, with
the hottest supported card being the Radeon
HD 4870
. Our test card is a HD
, so lets hope the CoolMaxx is an overachiever.

Package contents.

Given the high price-tag one would also expect a better assortment of accessories.
The package includes only eight low profile memory heatsinks, nothing extra
for the voltage regulators, etc. and a manual fan speed controller which is
similar in design to Zalman’s Fanmate 2, though its has a rather odd shape.

ZEROtherm CoolMaxx 2000: Specifications
(from the product
web page
164(L) X 104(W) X 33.5(H) mm
(6.7 X 3.8 X 2.1 inch)
225 g
Pure Copper
Heat pipe
Pure Copper
Memory Heatsink
Fan Size
Fans Speed
1,000 ~ 2,700 rpm
(± 10%, Manual Speed Control)
Acoustic Noise
20 ~ 33 dBA (± 10%)
Bearing Type
Long Life Sleeve Bearing
Operating Voltage
12.0 DC
Life Expectance
50,000 Hours
Max. Airflow Rate

29.05 CFM (0.82m/Min)

Fan Connector
3 Pin (to M/B or to PSU)
Bundled Fan Speed Controller Specifications
34 X 80 X 24 mm (1.3 X 3.2 X 1.0 inch)
Extension Cable Length
1,000 mm (39.4 inch)
Output Voltage Range
5.0 ~ 11.0 VDC
25.10-3 Pin or Equivalent (to M/B or to PSU)


The CoolMaxx 2000 is composed of a copper base and heatpipes while its 53 fins
are made of aluminum. The entire assembly appears to be nickel-plated giving
it a shiny, futuristic look.

A 9 blade, 74mm diameter fan is secured using a plastic spine.
The cooler uses a four screw mounting system of which we approve — the
simpler the better. Keeping the fan cable snug against the side is a nifty
wire clip which can be easily lifted to release the cable from its grasp.


A compact cooler, the CoolMaxx only takes up only a single extra
expansion slot. The fins are 0.30mm thick and are spaced approximately
1.36mm apart.


We found the base to be fairly flat, but the like the Nirvana,
clear semicircular machines marks were easily visible. Despite this, it
did produce a nice reflection of the beaver on a Canadian nickel.


Installed on our test card, a Radeon HD 4890, the CoolMaxx looks
undersized. Our main concern is how well it can cool the voltage regulators
given that the fan is positioned directly over the GPU core, even though
the stock cooling plate is designed to spread the heat around.


From the side.


The memory heatsinks are 6mm tall and use a moderately thick
thermal adhesive pad. The ramsinks included with some third party manufacturers
utilize a thin, easily compromised adhesive film — this is far preferable.


Our test procedure is an in-system test, designed to determine whether the
cooler is adequate for use in a low-noise system. By adequately cooled,
we mean cooled well enough that no misbehavior related to thermal overload is
exhibited. Thermal misbehavior in a graphics card can show up in a variety of
ways, including:

  • Sudden system shutdown, reboot without warning, or loss of display signal
  • Jaggies and other visual artifacts on the screen.
  • Motion slowing and/or screen freezing.

Any of these misbehaviors are annoying at best and dangerous at worst —
dangerous to the health and lifespan of the graphics card, and sometimes to
the system OS.

Test Platform

Measurement and Analysis Tools

  • CPUBurn
    processor stress software.
  • FurMark
    stability test to stress the GPU.
  • GPU-Z to
    monitor GPU temperatures..
  • A custom-built variable fan speed controller to power the system
  • PC-based spectrum analyzer:
    SpectraPlus with ACO Pacific mic and M-Audio digital
    audio interfaces.
  • Anechoic chamber
    with ambient level of 11 dBA or lower

A summary of how our video card/cooler test platform is put together can
be found here.


Our test card, a Radeon HD 4890.

GPU coolers are tested on a HIS Radeon HD 4890 Turbo Edition, one of the most
power hungry single GPU cards on the market, drawing almost 150W by our estimates.
The stock heat plate is left on to cool the memory chips and the voltage regulators
as the 4870/4890 series requires good VRM cooling and the VRM heatsinks included
with most aftermarket VGA coolers are usually too small to be ineffective.

Our main test consists of FurMark stability test running in conjunction with
CPUBurn to stress both the graphics card and processor simultaneously. This
combination produces more CPU/GPU stress than a typical gaming session. As our
test system has very limited airflow, our results are not indicative of a real-world
situation, but rather a worse-case scenario. If the heatsink in question can
cool the card and its components adequately in this environment it means there
will be some degree of thermal headroom when deployed in a more conventional
situation. GPU temperatures are recorded using GPU-Z. On our HD 4890 test card,
there are three main on-die sensors, as well as three on the primary voltage
regulators. We average the results of each set of sensors.

The cooler is tested at various speeds to represent a good cross-section of
its airflow and noise performance. Noise is measured and recorded with our test
system on with the heatsink installed. Our mic is positioned at a distance of
one meter from the center of the case’s left side panel at a 45 degree angle.

Reference Comparison Results

Fan Voltage
Avg. Core Temp
Avg. VRM Temp
Accelero S1 (2 x Nexus 92mm 1500rpm)
16 dBA
15 dBA
Accelero S1 (2 x Scythe 100mm 1500rpm)
21 dBA
19 dBA
17 dBA


16 dBA
15 dBA
Scythe Musashi
23 dBA
19 dBA
17 dBA
15 dBA
14 dBA
Zalman VF1000 LED
22 dBA
22 dBA
20 dBA
19 dBA
17 dBA
Ambient temperature: 23°C
Ambient Noise Level: 11 dBA
(12 dBA with the test system on)


Test Results: ZEROtherm CoolMaxx 2000
Fan Voltage
Fan Speed
Avg. Core Temp
Avg. VRM Temp
2510 RPM
22~23 dBA
2030 RPM
20 dBA
1650 RPM
18 dBA
1210 RPM
15 dBA
Test Results: HIS 4890 Turbo Stock Cooler
2340 RPM
26 dBA
Ambient temperature: 23°C
Ambient Noise Level: 11 dBA
(12 dBA with the test system on)

@12V: The GPU core temperature was close to the stock cooler’s result, but
quieter by 3~4 dB. VRM cooling was a massive 30°C worse, due primarily to
the location of the fan. The HD 4890 stock heatsink has a clear advantage as
its fan blows directly over the voltage regulators. The generated noise was
loud, whiny and turbulent.

@9V: Core and VRM temperatures increased by 7°C and 12°C respectively.
At 9V the pitch of the fan lowered, producing a prominentt hum and a slight
rattle, though only up close. At 1m it sounded fairly smooth though measuring
20 dBA, it was louder than we would’ve liked.

@7V: Temperatures continued to increase, with the GPU core heating up an additional
5°C and the VRMs approaching 150°C. Acoustically, most of the fan’s
more troublesome characteristics disappear, leaving only a low pitched hum,
and at 18 dBA it can be considered quiet.

@5V: We discontinued testing as our test card typically fails when the VRMs
approach 155~160°C.

The cooler is more than capable of dealing with the GPU core of the HD 4890,
but without direct airflow over the voltage regulators, VRM temperatures soar,
especially when airflow is limited. The included fan controller allows the speed
to be adjusted from 1270 to 2410 RPM, which is approximately equivalent to 5V~12V,
but we wouldn’t use it under 9V on a HD 4870/4890.


Comparison @ 20 dBA (+/- 1 dB)
GPU Cooler
Avg. Core Temp
Avg. VRM Temp
Scythe Musashi @ 10V
19 dBA
Accelero S1 @ 11V
(2 x Scythe 100mm)
19 dBA
CoolMaxx 2000 @ 9V
20 dBA
Zalman VF1000 @ 9V
20 dBA

Core temperatures in the 90°C range may seem high, but it should be noted
that more impressive, dual fan coolers don’t perform particularly well on the
blistering hot HD 4890 either. At the 20 dBA level (+/- 1 dB), the CoolMaxx
matches the Scythe Musashi in core temperature, and beats the Accelero S1 (with
two 100mm Scythe fans strapped to it) by 4°C. Having a second fan definitely
has its advantages however, with both the Musashi and S1 posting a whopping
20°C lead in average VRM temperature over the CoolMaxx.

As far as single fan GPU coolers go, the CoolMaxx is formidable, besting the
heavier, all-copper Zalman VF1000 by 10°C in core temperature.


These recordings were made with a high
resolution, lab quality, digital recording system
inside SPCR’s
own 11 dBA ambient anechoic chamber
, then converted to LAME 128kbps
encoded MP3s. We’ve listened long and hard to ensure there is no audible degradation
from the original WAV files to these MP3s. They represent a quick snapshot of
what we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!

The recording starts with 10 seconds of room ambiance, followed by 10 seconds
of the VGA test system without a video card installed, and then the actual product’s
noise at various levels. For the most realistic results, set the volume
so that the starting ambient level is just barely audible, then don’t change
the volume setting again.



The ZEROtherm CoolMaxx 2000 is an excellent single fan GPU cooler, especially
when you consider its size. Whether by coincidence or not, the entire package
mirrors the Zalman VF1000
in several ways. The main design is almost the same with the exception of the
fan location and the use of aluminum instead of copper, and both mount very
easily and securely. The included fan controller is very Fanmate-like, and the
green low profile memory heatsinks are a close analog to Zalman’s blue ramsinks.
However, the CoolMaxx delivers much stronger performance, and slightly better
acoustics (though this is a relative improvement — the fan does not sound
particularly good).

Unfortunately, being a single fan heatsink, the CoolMaxx is limited, only suitable
for use with video cards that do not require direct VRM cooling like the GeForce
9800 or Radeon HD 4850,
at least if any semblance of quiet is desired. It actually cooled our HD 4890’s
GPU core very well, much better than expected considering the card’s power draw,
but it didn’t provide enough coverage over the rest of the PCB. With its fan
dialed down to what we consider a quiet level (7V), the CoolMaxx brought the
voltage regulators on our HD 4890
within 5~10°C of overheating, and that’s simply far too close for comfort.
By comparison, the Scythe Musashi,
a dual fan cooler, provides far superior VRM cooling (in the range of 20°C),
has superlative acoustics, and can be found for only $40 compared to the CoolMaxx’s
$55 price-tag.

Its cost is an anomaly given its performance, light weight and small size.
The previously mentioned VF1000 weighs 65% more and is composed almost entirely
of expensive copper, yet the CoolMaxx carries a $15 price premium over it. In
addition, the cards it is suited for are in the $100 range or lower, making
a $55 upgrade for a good, not great GPU cooler, seem like a very poor value.

ZEROtherm CoolMaxx 2000

* Good GPU core cooling
* Easy, secure installation
* Small, light
* Fan controller included


* Poor VRM cooling
* No extra VRM heatsinks
* Subpar acoustics
* Too expensive


Our thanks to ZEROtherm
for the CoolMaxx 2000 sample used in this review.

* * *

Articles of Related Interest
Musashi Dual Fan GPU Cooler

HIS Radeon HD 4890 Turbo Edition
Thermaltake Duorb VGA Cooler:
Are Two Orbs Better Than One?

Xigmatek Battle-Axe: First Direct-Touch
Heatpipe VGA Cooler

Arctic Cooling Accelero S2
VGA Cooler + Turbo Module

Arctic Cooling Accelero S1 VGA

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