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ZEROtherm CORE92 Direct-Touch CPU Cooler

ZEROtherm CORE92 CPU Cooler

May 4, 2009 by Lawrence Lee

Product
ZEROtherm CORE92

LGA775/1366 CPU Cooler
Manufacturer
ZEROtherm
Street Price
US$32~40

It has been over a year since Xigmatek made a splash with their direct-touch
heatpipe CPU coolers. The HDT-S1283 in particular, set a new standard for value,
performing at a level that almost matched the best CPU coolers, while costing
$20 to $30 less. It was also amazingly efficient, weighing only 600 grams —
the best tower coolers weigh close to a kilogram. The HDT-SD964, a smaller
92mm fan version also performed well, though it was overshadowed by its bigger
brother due to the small difference in price.

Since then, direct-touch heatpipes have spread, permeating throughout the industry
as other manufacturers jumped on the bandwagon. The basic design has not changed
however — most of them are simply clones of the original design, with minor
alterations if any. Nothing new, exciting, or simply different featuring these
heatpipes has really emerged.



The box.

ZEROtherm's CORE92 is an exception. ZEROtherm's designs have typically
been pleasing to the eye, and their first foray into direct-touch heatpipe coolers
follows the trend. The CORE92 is a LGA775/1366 direct-touch cooler with a fan
embedded into the center of the heatsink body.



Box contents. The CORE92 uses a single set of installation brackets for
both LGA775 and LGA1366 installation, and with the fan embedded, there
really is a need for many accessories.

ZEROtherm CORE92: Key Features
(from the product
web page
)
Feature & Brief
Our Comment
Best Performance among 92mm air cooling
CPU coolers
That remains to be seen.
Heatpipe Direct Touch

Effective 6-line Heat pipe effect
Coolers with Direct Touch heatpipes are
proven performers.
Automatic Fan Speed Control (PWM) Standard issue.
Fin-Fan-Fin Structure

Max 29.5 dBA at 2,500 rpm
Coolers with imbedded fans usually disappoint.
Easy to install

Push-pin-type Universal LGA 775 / 1366 Clip
Not ideal, but for a light weight heatsink,
it's an acceptable method.
Supports Intel LGA1366

Core i7 and LGA775

Core 2 Quad, Core 2 Duo

and Pentium 4
Only supports Intel platforms. Developing
an AMD mounting bracket would've been simple enough.
Super Bright LEDs If you're into that kind
of thing.


ZEROtherm CORE92: Specifications
(from the product
web page
)

PHYSICAL DETAILS & INSTALLATION



The CORE92 is a tower cooler with an imbedded 92mm fan and three heatpipes.
Each fin is approximately 0.34 mm thick and spaced an average of only
1.54 mm apart.



At the top of the cooler is a metallic cover which is attached via two
Philips head screws to the heatsink body. The fan is secured to the cover
using black plastic rivets.



The base is composed of three heatpipes flattened smooth against a mounting
plate from which the metal installation brackets dangle lacksidasically
The holes on the brackets are long, allowing the pushpins to slide outward
to accommodate the wider mounting foot print of LGA1366 sockets.


The base is very flat and has an impressive shine. Compared
to Xigmatek style
direct-touch heatpipe coolers, the gaps between the heatpipes are much
smaller. The more heatpipe surface area over the center of the CPU heatspreader,
the better.




Installed on our test platform. Its small overall size makes it easily
compatible with most cases. The CORE92 weighs only 450 grams.


FAN REMOVAL



Unscrewing two screws on the top cover allows the fan to be
pulled out. As the cover sits atop the loosely support fins, we suspect
it is highly susceptible to vibration.




The fan is held onto the cover by four plastic rivets. They are completely
secure and easy to remove/install.




Fan assembly taken apart.





Fan assembly with our reference Nexus fan.

TESTING

Before thermal testing, we took some basic physical measurements.

ZEROtherm CORE92:
Approximate Physical Measurements
Weight
450 g
Fin thickness
0.34 mm
Fin spacing
1.54 mm
Vertical Clearance
43 mm (measured from the
motherboard PCB to the heatsink's bottom fin)
Horizontal Overhang
N/A (measured from the
edge of the heatsink to the top edge of our test motherboard's PCB)


Comparison: Approximate Fin Thickness & Spacing
Heatsink
Fin Thickness
Fin Spacing
Scythe Ninja 2
0.39 mm
3.68 mm
Thermalright HR-01 Plus
0.45 mm
3.15 mm
Noctua NH-U12P
0.44 mm
2.63 mm
Noctua NH-C12P
0.47 mm
2.54 mm
Prolimatech Megahalems
0.50 mm
2.00 mm
Xigmatek HDT-S1283
0.33 mm
1.96 mm
Cooler Master Hyper N520
0.38 mm
1.72 mm
Xigmatek HDT-SD964
0.33 mm
1.72 mm
ZEROtherm CORE92
0.34 mm
1.54 mm
Thermalright Ultra-120
0.45 mm
1.42 mm

Testing was done according to our
unique heatsink testing methodology
, and the included fan was profiled
using our standard fan testing
methodology
. A quick summary of the components, tools, and procedures
follows below.

Key Components in Heatsink Test Platform

  • Intel
    Pentium D 950
    Presler core. TDP of 130W; under our test load, it measures
    78W including efficiency losses in the VRMs.
  • Asus P5Q-EM motherboard. A microATX board with integrated graphics
    and short solid-state capacitors around the CPU socket, and a diminutive northbridge heatsink for maximum compatibility.
  • Intel X25-M
    80GB 2.5" solid-state drive.
  • 1GB of Corsair XMS2 DDR2 memory. 2 x 512MB PC2-8500.
  • FSP Zen 300W
    fanless power supply.
  • Arctic Silver
    Lumière
    : Special fast-curing thermal interface material, designed
    specifically for test labs.
  • Nexus 92 fan (part of our standard testing methodology; used when
    possible with heatsinks that fit 92x25mm fans)

Measurement and Analysis Tools

  • Seasonic
    Power Angel
    for measuring AC power at the wall to ensure that the
    heat output remains consistent.
  • Custom-built, four-channel variable DC power supply, used to regulate
    the fan speed during the test.
  • 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
  • Various other tools for testing fans, as documented in our
    standard fan testing methodology
    .
  • SpeedFan, used to monitor the on-chip thermal sensor. This sensor is not
    calibrated, so results are not universally applicable.
  • CPUBurn
    P6
    , used to stress the CPU heavily, generating more heat than most
    real applications. Two instances are used to ensure that both cores are stressed.
  • Throttlewatch
    2.01
    , used to monitor the throttling feature of the CPU to determine
    when overheating occurs.

Load testing was accomplished using CPUBurn to stress the processor, and the
graph function in SpeedFan was used to make sure that the load temperature was
stable for at least ten minutes. The stock fan was tested at various voltages
to represent a good cross-section of its airflow and noise performance.

TEST RESULTS

Stock Fan Testing

The stock fan is constructed of rigid, translucent plastic to scatter the light
from two blue LEDs. Its blades have hooked leading edges and almost straight
trailing edges, similar to the venerable Yate Loon D12SL-12.



Stock Fan Specifications
Manufacturer Power
Logic
Power Rating 2.4 W
Model Number PLA09225S12M Airflow Rating 56.7 CFM
Bearing Type Sleeve RPM Rating 900~2500 RPM
Hub Size 1.54" Noise Rating Under 19.5 dBA
Frame Size 92 x 92 x 25 mm Header Type 4-pin PWM
Weight 90 grams Starting Voltage 4.3V
The data in the blue cells is provided by the manufacturer;
we measured the data cited in the green cells


TEST MEASUREMENTS
Voltage
Noise Level
Speed
12V
34 dBA
2340 RPM
9V
20 dBA
1510 RPM
7V
16 dBA
950 RPM
6V
15 dBA
690 RPM
5V
11 dBA
450 RPM

Fan @ 12V: The fan was extremely loud, with a whiny, high-pitched drone
and a heavy amount of turbulence. Very tonal.

Fan @ 9V: The noise level dropped off significantly. The fan's pitch
lowered to a more tolerable hum. At this level the metal fan cover started to
rattle from vibration.

Fan @ 7V: The noise level reached what we would consider 'quiet' though
the hum from the fan's bearing was still noticeable. More annoying was the rattle
of the top cover — tightening the screws reduced this dramatically.

Fan @ 5V: The fan was all but inaudible at one meter's distance. Up-close,
the bearing was very clicky.

Overall the fan sounds like a typical translucent fan, harsh at high speed,
and mildly agitating at low speed.

Cooling Results

ZEROtherm CORE92 w/ stock 92mm fan
Fan Voltage
Temp
°C Rise
°C/W
12V
34 dBA
29°C
9
0.12
9V
20 dBA
32°C
12
0.15
7V
16 dBA
39°C
19
0.24
6V
15 dBA
49°C
29
0.37
5V
11 dBA
64°C
44
0.56
ZEROtherm CORE92 w/ reference 92mm fan
12V
18 dBA
46°C
26
0.33
9V
13 dBA
52°C
32
0.41
7V
11 dBA
60°C
40
0.51
Load Temp: CPUBurn for ~10 mins.

°C Rise: Temperature rise above ambient (20°C) at load.

°C/W: based on the amount of heat dissipated by the CPU (measured
78W); lower is better.

The CORE92's overall performance was surprisingly good with high airflow. With
the fan at full speed, the CPU temperature was only 9°C above ambient, matching
the lowest result we have ever achieved. Sure, the noise level was terrible
but this is still an impressive feat for a heatsink equipped with a 92mm fan.
When the fan voltage was reduced to 9V, the noise level was cut dramatically
while performance only suffered by 3°C. Clearly the inclusion of a 2300
RPM fan was overkill.

At 7V the CORE92's fan measured 16 dBA — equivalent to our reference Nexus 120mm fan at 12V. Thermal rise at this level was 19°C, only a couple of degrees shy of the Scythe Ninja 2.
At 6V, the difference in noise was negligible, but the CPU temperature climbed
by 10°C. At this point the CORE92 started to perform more like a 92mm cooler.
At 5V, the fan reached our anechoic chamber's noise floor and performance degraded
by an additional 15°C.

Switching the fan to our reference 92mm model did not result in better temperatures,
at least not until the fan was dialed back to the point where it was completely
inaudible at one meter's distance. Despite the measured noise level, the Nexus
92mm fan sounded much better at 12V than the ZEROtherm stock fan until its speed
was lowered to about 6V, though up close the difference was still noticeable.
Unfortunately the Nexus fan simply doesn't generate the amount of pressure and
airflow the CORE92 requires to perform well.

Comparables

The CORE92 does very well compared to other 92mm coolers, even the Coolermaster N520, which is equipped
with two fans.

ZEROtherm CORE92: Comparables
SPL @1m
Cooler Master

Hyper N520
Zalman

CNPS9300
ZEROtherm

CORE92
dBA
°C Rise
37
14
34
9
30
17
17
25
18
23
19
21
23
20
12
19
22
16
19
15
29
14
29

At higher fan speeds (generating 20 dBA and higher), the CORE92 easily beats the other two coolers above. It's only at the lowest fan speeds that the Hyper
N520

performance matches that of the Zerotherm.

Thermal Rise:

ZEROtherm CORE92 vs. Xigmatek HDT-SD964
Fan Voltage
HDT-SD964
CORE92
12V
21
26
9V
26
32
7V
31
40
Both heatsinks equipped with reference 92mm fan.

Compared to Xigmatek's 92mm direct-touch heatpipe cooler, the HDT-SD964,
the CORE92 does not fare as well. Using our very quiet, but low airflow reference Nexus 92mm fan, it lost
by 5°C at 12V, 6°C at 9V and 9°C at 7V. The SD964 has four heatpipes
vs. the CORE92's three, though we don't think that was the deciding factor.
The SD964's heatpipes are spaced so far apart that the ones at the edges barely
make contact with the CPU heatspreader.

Most likely, the CORE92's tightly-spaced fins increase airflow resistance so that our reference Nexus fan, with its low airflow, has a tough time pushing
air through it. The embedded fan design doesn't help here, as it increases the
amount of pressure required to pull air in.

MP3 SOUND RECORDINGS

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 second segments of room ambiance, then the fan
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.

FINAL THOUGHTS

The CORE92's direct-touch heatpipe technology is implemented well. By making them tightly-spaced, good, efficient
contact with the center of the CPU heatspreader is ensured — possibly the most important
factor in transferring heat. Other aspects of the design are less ideal, at least from a quiet cooling point of view. While cooling performance is excellent with the stock fan at the default 12V, the noise level is high and obtrusive. When the
fan speed is decreased, airflow is choked due to the tight fin spacing and the position of the fan in the center.
Surrounded by densely packed fins, with little breathing room, quiet CPU cooling is a challenge.

The fan is reminiscent of Zalman and Thermaltake models.
Rarely do we find a translucent fan that is quiet and this
fan is no exception. ZEROtherm would be wise to ditch the blue LED motif that
so many manufacturers seem to think is an absolute necessity. Doing so would
allow them to use smoother sounding fans. In addition, the stock fan has
a much higher top speed than necessary, though this will result in
the CORE92 scoring much better on review sites that do not take noise into consideration.
It is a truly impressive high airflow cooler.

The way the fan is mounts is not ideal — attaching it to a metal
frame is never a good idea. The rattle it produces is noticeable, though reduced
when the top cover is secured more tightly. If the fan was mounted on the outside, there would be for more flexible soft-mounting options.
Such a configuration probably wouldn't hurt performance as the distance the
air has to travel through the heatsink
would still be fairly short.

The heatsink mounting system could also use some work. We don't mind pushpins
for a low-weight cooler, but they could have been implemented better. It is neat
that the pins can simply be slid into the correct position for the CPU
socket, but there is nothing to hold them in place once there. After placing
the cooler onto the CPU, we found the pushpins pointing every which way, and getting
them into proper position was tedious. Doing this inside a case would
be tricky, especially for LGA775 motherboards as the heatsink body overhangs
where the pushpins need to be. The lack of support for AMD processors is another negative.

After reading all our comments, you may think this is a terrible
cooler, but despite its shortcomings, the Zerotherm Core92 is a pretty good performing
heatsink for its size. Our remarks sound negative because there are several
fundamental design flaws, which if corrected, could make
the CORE92 the ultimate 92mm low-noise CPU cooler. It does very well when the
fan speed is cranked up high, but when it is lowered to quiet levels, its performance
advantage erodes in dramatic fashion. For many users, however, the stock cooler with its fan controlled by a good motherboard-embedded fan controller could well be cool and quiet enough; 16 [email protected] for 19°C temperature rise is plenty good for many a system. A key issue is price, of course. At the current $32~40 market price, it's probably a bit too high compared to the Xigmatek HDT-SD964's $25~32. On the other hand, if noise is no concern, the Core92 is a very good, price-competitive cooler.


ZEROtherm CORE92
PROS



* Excellent cooling w/ high airflow

* Relatively small, light

* LGA1366 compatibility
CONS



* Loud fan
* Poorer cooling with low airflow

* Mounting needs improvement

* Lack of AMD compatibility

Our thanks to ZEROtherm
for the CORE92 heatsink sample.

* * *

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Thermaltake SpinQ: Unique Blower-fan
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Xigmatek HDT-S1283 &
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* * *

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