AMD Phenom II Stock Coolers

The Phenom II AM3 stock heatpipe cooler currently shipping with AMD’s 125W quad/hex core processors is pitted against the older, but larger AM2+ model. Is either heatsink worthwhile for quiet cooling?

June 13, 2010 by Lawrence Lee

Product
AMD Phenom II AM2+
Stock
CPU Cooler
AMD Phenom II AM3
Stock CPU Cooler
Manufacturer
AMD AMD
Street Price
N/A N/A

AMD is no stranger to heatpipes, having used them in their desktop stock coolers
since the days of socket 939. Not only did their dual core processors outperform
Intel’s at the time, the introduction of stock heatsinks with heatpipes for
their higher power chips was a very popular move. Back then a CPU cooler with
heatpipes would run you at least US$30~$40, so to get a high performance processor
with a quality heatsink included was a big deal.

The Core i7-980X stock cooler was a first for Intel, a heavy, tower heatpipe
heatsink with a large fan and bright blue LEDs. It easily outmuscled the traditional
spiral heatsink with a copper core that ships with lower-end Core i7s. Recently
AMD also released a six core CPU based on the “Thuban” core and like
Intel, the new chip retained the same TDP as its quad core brothers, in AMD’s
case, 125W. But unlike Intel, they decided to stand pat with their stock heatsink,
believing it to be adequate cooling solution for their new hex core processor.
To better judge this assessment, we’ll put the current stock heatsink through
its paces as well as their previous version, which oddly enough, is actually
a bigger, more imposing cooler.


Old school AMD heatpipe cooler on the left, updated model on the right.

We are not 100% certain about the origin of the heatsink model pictured above
left, but it appears to be the same heatsink that ships with the Phenom II 920/940
(the fastest AM2+ CPUs produced) and older power hungry AM2 processors like
the Athlon 64 X2 6000+ and 6400+. Suffice it to say, if you bought a desktop
AM2/AM2+ processor with a TDP of more than 100W, this (or something very similar)
was the cooler you received. The one on the right is the updated version, shipping
with 125W AM3 processors like the Phenom II 955/965 and the new hex-core Thuban
CPUs


The Phenom II AM2+ stock cooler.


The Phenom II AM3 stock cooler.

Both of these AMD stock heatpipe coolers have the same basic components, a
large copper base soldered to two heatpipes, aluminum fins spaced tightly together,
and a fan with a wingspan of about 65 mm attached with the help of a plastic
cover. The body of the old style cooler is larger though, both in height and
width, and heavier by 80 grams. The new version seems to have sacrificed some
heft in order to use a thicker fan with a traditional box frame.

Approximate Physical Measurements
Heatsink AMD Phenom II AM2+ stock
cooler
AMD Phenom II AM3 stock
cooler
Dimensions
(L x W x H)
108 x 92 x 62 mm 92 x 91 x 62 mm
Weight
440 g 360 g
Fan Speed (max) 4000 rpm 3280 rpm
Fan Blade Wingspan
64 mm 65 mm
Fan Hub Size
32 mm 31 mm

AMD Phenom II AM2+ Stock Cooler: Physical Details

The AMD Phenom II AM2+ stock cooler is composed of two heatpipes,
a large copper base, and 59 aluminum fins. It measures 108 x 92 x 62 mm (L x
W x H) and weighs 440 grams.


Like all of AMD’s coolers, the AM2+ stock heatsink uses a spring-loaded
retention clip.


The fins are 0.31 mm thick and spaced 1.03 mm apart on average. The fan
is attached via plastic latches.


The fan is imbedded in the heatsink center. Proportionally, the hub is
very large with a diameter almost half the length of the fan’s 64 mm wingspan.


The base is a large copper plate running down the length of the heatsink.
It has a rough, unpolished finish.


Mounted on our test platform.

AMD Phenom II AM3 Stock Cooler: Physical Details

The AMD Phenom II AM3 stock cooler is composed of two heatpipes,
a large copper base, and 48 aluminum fins. It measures 92 x 91 x 62 mm (L x
W x H) and weighs 360 grams.


Both coolers are 62 mm tall but the AM3 model has a bigger fan and a smaller
heatsink.


While the fins are similar in thickness and spacing to the AM2+ version,
the total fin area is lower. The AM3 model has 11 fewer fins — the difference
is easily noticed.


The AM3 cooler has a different fan design, taller and with broad, flat
blades, though the hub size and wingspan are almost identical.


Oddly, the AM3 cooler’s base extends outward at the corners like a bearskin
rug.


Installed on our test platform.

TESTING

Before thermal testing, we took some basic physical measurements.

Approximate Physical Measurements
Heatsink AMD Phenom II AM2+ stock
cooler
AMD Phenom II AM3 stock
cooler
Fin count 59 48
Fin thickness
0.31 mm 0.33 mm
Fin spacing
1.03 mm 1.05 mm
Vertical Clearance*
N/A N/A
Horizontal Overhang**
-15 mm -17 mm
* measured from the motherboard PCB to
the bottom fin of the heatsink.
** measured from the far edge of the heatsink to the top edge of the motherboard
PCB.

 

Comparison: Approximate Fin Thickness & Spacing
Heatsink
Fin Thickness
Fin Spacing
Phenom II AM2+
stock cooler
0.31
1.03 mm
Phenom II AM3
stock cooler
0.33
1.05 mm
Scythe Big Shuriken
0.33 mm
1.19 mm
Scythe Samurai ZZ
0.33 mm
1.74 mm
Gelid Silent Spirit
0.36 mm
1.77 mm
Xigmatek HDT-SD964
0.38 mm
1.86 mm
Arctic Cooling Alpine 64
0.87 mm
2.11 mm
Scythe Ninja Mini
0.42 mm
3.46 mm

Testing was done on our
AM3 heatsink testing platform
which is designed for smaller CPU coolers.
A summary of the test system and procedure follows.

Key Components in Heatsink Test Platform:

  • AMD Athlon II X4 630 AM3,
    2.8GHz, 45nm, 95W TDP.
  • Asus M4A785TD-V EVO ATX motherboard.
    785G chipset.
  • Kingston
    SSDNow V
    30GB 2.5″ solid-state drive. Chosen for silence.
  • 2GB
    Corsair Dominator
    DDR3 memory. 2 x 1GB DDR3-1800 in dual channel.
  • FSP Zen 300W
    ATX power supply. Fanless.
  • Arctic Silver
    Lumière
    : Special fast-curing thermal interface material, designed
    specifically for test labs.
  • Nexus 120 fan (part of our standard testing methodology; used when
    possible with heatsinks that fit 120x25mm fans)
  • Nexus 92 fan (part of our standard testing methodology; used when
    possible with heatsinks that fit 92x25mm fans)

The system is silent under the test conditions, except for the CPU cooling
fan(s). At full load, the total system power draw is 132~140W AC, with the CPU
and VRMs drawing 85~91W DC (measured from the AUX12V connector), depending on
their respective temperatures.

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

Reference Nexus 120mm fan
Anechoic chamber measurements
Voltage
SPL@1m
Speed
12V
16 dBA
1100 RPM
9V
13 dBA
890 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.
  • CPUBurn,
    used to stress the CPU heavily, generating more heat than most real applications.
  • 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 CPUBurn 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 stock fan was 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 20~22°C.

Stock Fan Measurements: Phenom II AM2+ Stock Cooler

Stock Fan Measurements
Voltage
Speed
SPL @1m
12V
4000 RPM
36 dBA
9V
2860 RPM
26 dBA
8V
2330 RPM
20 dBA
7V
1650 RPM
14 dBA
6V
1350 RPM
12 dBA
Measuring mic positioned 1m at diagonal angle from
the intake side of the fan.
Ambient noise level: 11 dBA.

The Phenom II AM2+ stock cooler at full speed produces an extremely whiny,
earsplitting 36 dBA@1m thanks to its ridiculous 4000 RPM fan speed. At 9V, the
whine lessens allowing air turbulence to contribute to the acoustic profile.
At 8V, the noise level becomes bearable, surprisingly smooth, but a little buzzy
at times. At 7V it is smooth and quiet, and just barely audible with a SPL of
only 14 dBA@1m. At 6V it generates a very faint buzz that is only audible in
a dead quiet environment like our anechoic chamber.

Stock Fan Measurements: Phenom II AM3 Stock Cooler

Stock Fan Measurements
Voltage
Speed
SPL @1m
12V idle/load
3280 RPM
30 dBA
9V idle/load
2350 RPM
21~22 dBA
7V load
(~8.4V)
2100 RPM
19~20 dBA
6V load (~7.5V)
1800 RPM
17 dBA
7V idle
1650 RPM
15~16 dBA
5V load
(~6.7V)
1510 RPM
15 dBA
6V idle
1290 RPM
13 dBA
5V idle
910 RPM
11~12 dBA
Measuring mic positioned 1m at diagonal angle from
the intake side of the fan.
Ambient noise level: 11 dBA.

The AM3 stock cooler’s fan has a lower top speed, but is still very loud at
this level, emitting 30 dBA@1m in a mostly whiny and turbulent manner. At 9V
it produces an aggressive low-pitched growl. At 7V, it is a little buzzy, but
fairly smooth and broadband otherwise. At 6V, there is a slight hum that is
just audible.

The fan also appeared to be temperature controlled as during load testing at
7V and below, the fan speed increased even though it was being powered by an
external power supply (the RPM sensor wire was connected to a motherboard fan
header for real-time fan speed monitoring). When paired with our Athlon II X4
630 test processor, it would not run quieter than 15 dBA@1m on load.


Fan speed measured by SpeedFan. The fan speed increased during load despite
the fact we fed it a steady 6V from an external source.

COOLING RESULTS

AMD Phenom II AM2+ Stock Cooler w/ stock fan
Fan Voltage
SPL@1m
Temp
°C Rise
12V
36 dBA
40°C
20
9V
26 dBA
49°C
29
8V
20 dBA
56°C
36
7V
14 dBA
62°C
42
6V
12 dBA
73°C
53
°C Rise: Temperature rise above ambient (20°C)
at load.

The AM2+ stock cooler has a very wide range of performance depending on how
fast the fan is spinning. It delivered excellent results at 9V and above, but
at quieter levels, its cooling proficiency fell almost linearly with dBA. At
8V, the noise level was 6 dBA lower with a performance penalty of 7°C. At
7V it dropped another 6 dBA at the cost of 6°C. In this sense, its performance
scales consistanly, at least until 6V when the lack of airflow really degrades
its efficiency.

AMD Phenom II AM3 Stock Cooler w/ stock fan
Fan Voltage
SPL@1m
Temp
°C Rise
12V
30 dBA
49°C
28
9V
21~22 dBA
55°C
34
7V (8.4V)
19~20 dBA
64°C
43
6V (7.5V)
17 dBA
67°C
46
5V (6.7V)
15 dBA
74°C
53
°C Rise: Temperature rise above ambient (21°C)
at load.
Dark gray boxes indicate failure CPU throttling, failure.

Due to the thermally-controlled fan, the AM3 stock cooler simply isn’t capable
of functionally as quietly as we would like. It performed well at 9V and above
but the noise level wasn’t great. When manually fed 7V and lower, the fan sped
up to the equivalent of 1.4V~1.7V higher. The temperatures generated at 6V &
7V were average, while 5V caused the CPU to throttle.

It should be noted that our test CPU has a TDP of only 95W, while the AM3
heatpipe cooler ships with processors rated for 125W.

Comparison Chart

°C rise Comparison
SPL (dBA@1m)
20
19
18
17
16
15
14
13
12
11
Ninja Mini (ref. fan)
23
27
HDT-SD964
22
27
34
Samurai ZZ
29
30
32
Big Shuriken
26
30
37
37
Silent Spirit
25
35
43
53
Alpine 64
34
43
46
Phenom II AM2+
36
42
53
Phenom II AM3
43
46
53
Dark gray boxes indicate failure CPU throttling, failure.

Compared to some reasonably sized third party heatsinks, the larger AM2+ cooler
performs about as well as the Arctic Cooling Alpine 64 at the 14~15 dBA level,
but is beaten by 7°C at 12 dBA. The smaller AM3 model trails the AM2+ cooler
by 7°C at 19~20 dBA, and falls 8°C behind the Alpine 64 at 17 dBA. Its
failure at the 15 dBA level is a bit odd as the Silent Spirit and AM2+ cooler
managed to remain stable at the same thermal rise. It may be that the lack of
airflow caused the VRMs to overheat.

Perhaps the easiest way to judge their relative performance is to see how noisy
each cooler is when the thermal rise above ambient reaches 42~43°C (results
bolded), not a particularly lofty goal. The AM3 cooler hits it at 20 dBA, the
Alpine 64 at 15 dBA, the AM2+ cooler at 13~14 dBA, and the Gelid Silent Spirit
at 13 dBA. The rest of the field can accomplish this result while being effectively
inaudible.

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.

Comparable CPU cooler sound files:

FINAL THOUGHTS

The updated heatpipe cooler that AMD ships with their high power AM3 processors
is rather disappointing compared to the previous AM2/AM2+ version. Switching
to a smaller heatsink with a thicker fan resulted in a significant drop in thermal
performance. It managed to cool our processor adequately at a reasonably quiet
17 dBA@1m, but at 15 dBA@1m it failed completely, causing the CPU to throttle.
This is the first time this has occurred on our AMD heatsink test platform which
is driven by a 95W TDP Athlon II X4 630. If tasked with keeping a 125W Phenom
II X4/X6 stable at full load, the minimum operating noise level would be much
higher.

The older stock heatpipe cooler is heftier and despite its thinner fan, is
a much stronger heatsink. At noise levels around 14~15 dBA@1m, its cooling proficiency
is more or less equal to that of the Arctic Cooling Alpine 64, one of the most
popular budget AMD heatsinks. It would actually be a better choice in cases
with a low CPU heatsink height limit as the Alpine 64 is 3 cm taller. In that
situation, it’s well worth shelling out say $10 for one.

While these two heatsinks are lacking in performance like most stock coolers,
the fan on both models have decently smooth acoustics once undervolted. All
the Intel stock coolers we’ve
used have a very dry-sounding tonal hum that doesn’t go away unless the fan
is set to near inaudible levels. When compared at equivalent measured noise
levels, the AMD fans sound smoother by a country mile.

Our thanks to AMD
for the stock heatsink samples.

* * *

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* * *

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