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Cooler Master GeminII M4 Low Profile Heatsink

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Cooler Master’s GeminII M4 bears more than a passing resemblance to the Scythe Big Shuriken 2. If imitation is the sincerest form of flattery, the M4 is only a half-hearted compliment.

July 15, 2012 by Lawrence Lee

Product
Cooler Master GeminII M4
CPU Cooler
Manufacturer
Cooler Master
Street Price
US$30

Back in 2009, we did a couple of roundups of smallish CPU heatsinks which consisted of some petite stock unit replacements and performance coolers of varying sizes. The 86 mm tall Cooler Master GeminII S was one of the reviewed models, but today it wouldn’t even qualify as a compact heatsink. The proliferation of mini-ITX motherboards and cases over the past two years has fueled the need for smaller coolers, closer to 60 mm or less in height.


The Cooler Master GeminII M4.

The latest GeminII, the M4, is more contemporary with today’s standards. It bears more than a passing resemblance to one of the best small heatsinks on the market today, the Scythe Big Shuriken 2. Its dimensions are almost identical, though the M4 is substantially lighter, and its slim 120 mm fan is a bit thicker. On paper, the other big difference is the use of four direct-touch heatpipes; the Big Shuriken 2 has five heatpipes and a copper base plate.


Package contents.

The box is no larger than it needs to be. The heatsink comes packed in a protective foam layer along with the accessories. The mounting hardware includes a backplate despite the M4’s low mass, and LGA2011 clips are provided right out of the box. There’s also an instruction sheet, a tube of thermal compound and a nut-driver.

Cooler Master GeminII M4: Key Features
(from the product
web page
)
Feature & Brief
Our Comment
Super low profile cooler (59mm / 2.3in height) with 4 direct contact heat pipes. For a smaller heatsink, four heatpipes seems like a lot but they’re quite short.
A base engineered to minimize CPU contact gaps provides excellent heat conduction. Okay.
Suitable for limited space applications (e.g. HTPC or slim systems). That’s why we’re here.
Newly developed thin fan profile delivers uncompromised cooling performance in a compact package. A thinner than normal fan is utilized to keep the size down.
Unique heat pipe layout combines two very effective cooling methods to increase cooling efficiency while maintaining a low profile heat sink. Direct-touch heatpipes contact the processor heatspreader directly, making a separate base plate unnecessary.

 

Cooler Master GeminII M4: Specifications
(from the product
web page
)
Model RR-GMM4-16PK-R2
CPU Socket Intel Socket:
LGA 2011 / 1366 / 1156 / 1155 / 775 *AMD Socket:
FM1 / AM3+ / AM3 / AM2+ / AM2
CPU Support Intel:
Core™ i7 Extreme / Core™ i7 / Core™ i5 / Core™ i3 / Core™2 Extreme / Core™2 Quad / Core™2 Duo / Pentium / CeleronAMD:
FX-Series / A-Series / Phenom™ II X4 / Phenom™ II X3 / Phenom™ II X2 / Phenom™ X4 / Phenom™ X3 / Athlon™ II X4 / Athlon™ II X3 / Athlon™ II X2 / Athlon™ X2 / Athlon™ / Sempron™
Dimension 137 x 122 x 59mm (5.4 x 4.8 x 2.3 in)
Heat Sink Dimensions 120 x 118 x 44 mm (4.7 x 4.6 x 1.7 in)
Heat Sink Material 4 Direct Contact Heat Pipes / Aluminum Fins
Heatsink Weight 210g (0.46 lb)
Heat Pipes Dimensions ø6mm
Fan Dimension 120 x 120 x 15 mm (4.7 x 4.7 x 0.6 in)
Fan Speed 500 – 1,600 RPM (PWM) ± 10%
Fan Airflow 17.4 – 58.4 CFM ± 10%
Far Air Pressure 0.18 – 1.76mm H2O ± 10%
Fan Life Expectancy 40,000hrs
Fan Noise Level (dB-A) 8 – 30 dBA
Bearing Type Long Life Sleeve
Connector 4-Pin
Fan Rated Voltage 12 VDC
Fan Rated Current 0.2A
Power Consumption 2.4W
Fan Weight 79g (0.17 lb)
Warranty 2 years
UPC Code 884102013140
Notice * Supplied accessories may differ by country or area. Please check with your local distributor for further details.

PHYSICAL DETAILS

The Cooler Master GeminII M4 is composed of four 6 mm thick copper direct-touch heatpipes surrounded by 56 aluminum fins. With the fan mounted, it measures 137 x 122 x 59 mm (W x D x H) and weighs about 280 grams total.


The heatsink is considerably thicker at the center, tapering off toward the edges. For some reason, the fins at one end are shorter, leaving empty corners for the fan to blow through.


The heatpipes are quite short, forming a very tight “C” shaped curve. The fan clips are surprisingly loose.


The fan blades are translucent but there are no LEDs. Like some other slim 120 mm fans we’ve seen, the struts are reinforced with a ring running around the space between the hub and fan blade edges.


The fins measure 0.29 mm thick. Average spacing is approximately 1.46 mm.

 


Like all direct-touch heatpipes we’ve encountered in the past, the base has a flat but fairly rough surface.

INSTALLATION

The most critical aspect of installation is that the heatsink
be securely mounted. A firm mating results in good contact between the heatsink’s
base and the CPU heatspreader and more efficient heat conduction. Ideally it
should also be a simple procedure leading to consistent results with the user having to handle as few pieces
of hardware as possible.


The GeminII M4 uses a mounting system similar to previous Cooler Master heatsinks. The first step is to screw in the mounting clips.


The bolts are spring-loaded — depressing the spring allows you to slide it horizontally to the appropriate hole for the Intel socket of your choosing.


The heatsink is flipped upside-down with the bolts protruding through the mounting holes around the socket. A backplate is lined up with them and nuts are used to secure it in place. A nut-driver is provided to make things easier.


Installed on our LGA1155 test platform.


The clearance below the inner portion of the heatsink is just 26 mm, the same height as the VRM heatsink on our test motherboard.

TESTING

Before thermal testing, we took some basic physical measurements.

Approximate Physical Measurements
Weight
200 g
280 g with stock fan and clips
Height 59 mm
Fin count 56
Fin thickness
0.29 mm
Fin spacing
1.46 mm
Vertical Clearance*
26 mm (inner section)
44 mm (outer section)
* measured from the motherboard PCB to
the bottom fin of the heatsink.

 

Small Heatsink Comparison:
Average Fin Thickness & Spacing
Heatsink
Fin Thickness
Fin Spacing
Scythe Big Shuriken 2 Rev.B
0.29 mm
1.13 mm
Scythe Big Shuriken
0.33 mm
1.19 mm
Reeven Vanxie
0.28 mm
1.39 mm
Reeven Arcziel
0.28 mm
1.41 mm
Cooler Master GeminII M4
0.29 mm
1.46 mm
Noctua NH-L12
0.49 mm
1.51 mm
Scythe Kozuti
0.12 mm
1.69 mm
Scythe Samurai ZZ
0.33 mm
1.74 mm

Testing on larger heatsinks are done on our
LGA1366 heatsink testing platform
, while smaller coolers like this CoolerMaster tackle our LGA1155 heatsink testing platform. A summary of the test system
and procedure follows.

Key Components in LGA1155 Heatsink Test Platform:

The systems are silent under the test conditions, except for the CPU cooling
fan(s).

Normally, our reference fans are used whenever possible, the measured details
of which are shown below.

Reference Noctua 140mm fan
Anechoic chamber measurements
Voltage
SPL@1m
Speed
12V
28~29 dBA
1250 RPM
9V
21 dBA
990 RPM
7V
15~16 dBA
770 RPM
6V
13 dBA
660 RPM

 

Reference Nexus 120mm fan
Anechoic chamber measurements
Voltage
SPL@1m
Speed
12V
16 dBA
1080 RPM
9V
13 dBA
880 RPM
7V
12 dBA
720 RPM

 

Reference Nexus 92 mm fan
Anechoic chamber measurements
Voltage
SPL@1m
Speed
12V
16 dBA
1470 RPM
9V
12 dBA
1150 RPM

Measurement and Analysis Tools

  • Extech 380803 AC power analyzer / data logger for measuring AC system
    power.
  • 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 sensors. The sensors are not calibrated,
    so results are not universally applicable. The hottest core reading is used.
  • Prime95,
    used to stress the LGA1366 CPU heavily, generating more heat than most real applications.
    8 instances are used to ensure that all 4 cores (with Hyper-threading) are
    stressed.
  • CPU-Z,used to monitor the CPU speed to determine when overheating occurs.
  • Thermometers to measure the air temperature around the test platform
    and near the intake of the heatsink fan.

Noise measurements are made with the fans powered from the lab’s variable DC
power supply while the rest of the system was off to ensure that system noise
did not skew the measurements.

Load testing was accomplished using Prime95 to stress the processor and the
graph function in SpeedFan was used to ensure that the load temperature is stable
for at least ten minutes. The temperature recorded is the highest single core
reading. The stock fans were tested at various voltages to represent a good
cross-section of airflow and noise performance.

The ambient conditions during testing were 10~11 dBA and 21~23°C.

STOCK FAN MEASUREMENTS

Specifications: Cooler Master GeminII M4 Stock Fan
Manufacturer
Power Rating
2.4 W
Model Number
FA12015M12LPA
Airflow Rating
17.4 ~ 58.4 CFM
Bearing Type
Sleeve
Speed Rating
500 ~ 1,600 RPM
Corners
Open
Noise Rating
8 ~ 30 dBA
Frame Size
120 x 120 x 15 mm
Header Type
4-pin
Fan Blade Diameter
113 mm
Starting Voltage
5.5 V
Hub Size
40 mm
Weight
80 grams
Data in green cells provided by the manufacturer
or observed; data in the blue cells were measured.

We’ve seen past Cooler Master fans with twisted blades and translucent blades but this is the first time we’ve seen both design elements together in the same unit. It’s a 15 mm thick, 13-blade, sleeve bearing fan with a 30 cm 4-pin cable

Stock Fan Measurements
Voltage
Speed
SPL@1m
12V
1580 RPM
30 dBA
9V
1240 RPM
24 dBA
7V
940 RPM
16~17 dBA
6V
770 RPM
14~15 dBA
5V
580 RPM
12 dBA
Measuring mic positioned 1m at diagonal angle from
the center of the heatsink.
Ambient noise level: 10~11 dBA.

The GeminII M4 fan is fairly inoffensive. Its acoustics are typical for a decent sleeve bearing fan. It has a buzzy and turbulent sound at higher speeds and is generally smooth at lower speeds. Being a 1,600 RPM model, it has quite a large noise range. The cooler is an almost inaudible 12 dBA@1m at 5V, while at 12V, it measures 30 dBA@1m.


Loose fan clips.

We’re not happy about the way the fan is mounted. The clips are so loose that an undesirable hum is generated by the interaction with the rest of the heatsink. As you can see in the image above, lifting the fan after the cooler is installed physically separates it from the heatsink.


Stock fan at 7V.

Naturally we wanted to see how much of a difference this issue made, so we slipped some foam padding under the four corners of the fan to make things tighter. This resulted in a noticeable improvement in acoustics. At the 7V level, a number of tonal peaks in the 120 ~ 1,500 Hz range dropped considerably and the overall noise level dropped by 1~2 dB.

Cooling Results

Cooler Master GeminII M4
Fan Voltage
Fan Speed
SPL@1m
°C Rise above Ambient
CPU
VRM
RAM
Stock Fan
12V
1580 RPM
30 dBA
45
24
16
9V
1240 RPM
24 dBA
47
27
18
7V
940 RPM
16~17 dBA
53
34
24
6V
770 RPM
14~15 dBA
56
38
26
5V
580 RPM
12 dBA
64
49
32
Reference Nexus 120mm Fan (+10mm)
12V
1080 RPM
16~17 dBA
48
25
19
9V
880 RPM
13 dBA
51
30
22
7V
720 RPM
11~12 dBA
54
32
23

The cooling performance was very disappointing. At the lowest tested stock fan speed (580 RPM/12 dBA), it was only about 10°C away from the CPU throttling, something that only happens to very small or very poor heatsinks. The sweet spot seemed to be somewhere between 770 and 940 RPM. Our thicker, reference Nexus 120 mm fan was significantly superior, especially at very low noise levels. The difference was about 10°C at the 11~12 dBA@1m level.

Heatsink Comparison Table

°C rise Comparison (CPU Temperature)
SPL (dBA@1m)
20
19
18
17
16
15
14
13
12
Noctua NH-L12
(both fans)
33
34
35
36
Noctua NH-L12
(ref. 120mm fan)
34
37
Scythe Big Shuriken 2 Rev.B
(ref. 120mm fan)
36
39
Noctua NH-L12
(120mm fan)
37
38
39
42
Scythe Big Shuriken
(ref. 120mm fan)
41
43
Scythe Big Shuriken 2 Rev.B
39
43
48
Reeven Arcziel
42
47
Scythe Samurai ZZ
(ref. 92mm fan)
44
51
Reeven Arcziel
(ref. 92mm fan)
41
52
Scythe Samurai ZZ
45
46
52
Cooler Master GeminII M4
(ref. 120mm fan)
48
51
54
Noctua NH-L12
(92mm fan)
42
44
47
51
57
Scythe Big Shuriken
43
46
61
Cooler Master GeminII M4
53
56
64
Scythe Kozuti
57
62
65
Reeven Vanxie
66
77
F

The GeminII M4 poses no threat to the Big Shuriken 2, generating CPU temperatures 13~16°C higher at similar noise levels. It’s not even a match for the now discontinued original Big Shuriken and only edges out the waifish Scythe Kozuti by a few degrees.

°C rise Comparison (VRM Temperature)
SPL (dBA@1m)
20
19
18
17
16
15
14
13
12
Noctua NH-L12
(both fans)
17
19
21
23
Noctua NH-L12
(ref. 120mm fan)
20
25
Scythe Big Shuriken
(ref. 120mm fan)
25
29
Scythe Big Shuriken 2 Rev.B
(ref. 120mm fan)
27
31
Noctua NH-L12
(120mm fan)
24
26
27
32
Cooler Master GeminII M4
(ref. 120mm fan)
25
30
32
Scythe Big Shuriken 2 Rev.B
29
34
39
Noctua NH-L12
(92mm fan)
28
31
33
38
43
Scythe Samurai ZZ
(ref. 92mm fan)
36
43
Reeven Arcziel
38
41
Scythe Big Shuriken
28
30
47
Reeven Arcziel
(ref. 92mm fan)
35
47
Cooler Master GeminII M4
34
38
49
Scythe Kozuti
36
40
45
Scythe Samurai ZZ
38
39
47
Reeven Vanxie
45
56
F

The GeminII M4’s VRM cooling is just as poor though it did improve substantially when paired with our thicker reference Nexus fan.

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 5~10 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

While the Cooler Master GeminII M4 resembles the Scythe’s Big Shuriken 2, its performance does not. At comparable noise levels, the Big Shuriken 2 beats it handily, with temperature differences in the double digit range. If the M4 had fared any worse, it might have even fallen behind tiny, 40 mm tall Scythe Kozuti.

Comparing the design of M4 to more successful heatsinks, one possible explanation for its poor performance becomes apparent. The Kozuti’s efficiency is thanks in part to its fan mounted directly over the heatsink base, blowing air over the CPU without any impedance. Our current champion, the Noctua NH-L12, has a similar setup but on a bigger scale. Not only does the GeminII M4 have a fin stack to blow through, the stack is thicker at the center above the CPU. The fins aren’t arrayed to take full advantage of the fan, either; there are naked spots underneath the fan in a couple of places. It seems to be a poor allocation of resources compared the Big Shuriken.

Another big issue is the incredibly loose fan clips. The fan is not adequately secured so the vibrations it produces are transmitted to the clips and heatsink fins, causing them to rattle against each other. This cases an annoying hum and increases the overall noise level. The fan itself actually has a fairly smooth sound but once you attach it to the heatsink, this positive impression fades.

It’s impossible for us to recommend the US$30 Cooler Master GeminII M4 when the Scythe Big Shuriken 2 can be had for only US$5 more. Its cooling ability is better by leaps and bounds, and it’s almost the exact same size. We do prefer the M4’s mounting system but that consideration is heavily outweighed by the Big Shuriken’s performance.

Our thanks to Cooler Master
for the GeminII M4 CPU cooler sample.

* * *

Articles of Related Interest

Reeven Kelveros & Arcziel CPU Coolers
Scythe Big Shuriken 2 & Reeven Vanxie CPU Coolers
Fans from Noctua & Corsair at Computex 2012
SPCR’s Updated 2012 Small CPU Heatsink Test Platform
Noctua
NH-L12 Low Profile Cooler

Scythe
Kozuti Low Profile CPU Heatsink

* * *

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this article in the SPCR forums.

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