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Zalman CNPS9900DF Dual Fan Flower Heatsink

The latest update to the iconic Zalman CNPS9900 series adds more girth and a second fan… in an ultimately futile attempt to get back to the top ranks of CPU coolers.

Zalman CNPS9900DF Dual Fan Flower Heatsink

October 8, 2012 by Lawrence Lee

Product
Zalman CNPS9900DF
CPU Cooler
Manufacturer
Zalman
MSRP
US$90

When the Zalman
CNPS9900 LED
CPU cooler was released in 2009, we thought it might be
the end of the flower series. We were almost certain of it when they launched
conventional tower coolers in 2010. To our surprise, they revived the 9900 in
2011 with the MAX,
which added nickel-plating and a larger fan. And now, in 2012, they’ve updated
it once again with the CNPS9900DF. It seems there is some life left in iconic
Zalman flower HS line after all. The "DF" stands for dual fans, following
in the footsteps of twin tower coolers like Noctua
NH-D14
and Thermalright
Silver Arrow
. Like these premier heatsinks, the DF carries a very high
MSRP, US$90. Zalman’s all-copper heatsinks have always been costly but
this takes it to another level.


The box.

As you can probably guess, it’s larger than its predecessor, sporting an extra
100 grams of bulk and a 26% higher heat dissipation area than the MAX. Instead
of one 140 mm high speed fan, the DF has both a 140 mm and 120 mm model with
more moderate speeds so it shouldn’t be much louder than the MAX, if at all.
We weren’t impressed by the MAX’s performance though so we’re not convinced
this latest iteration is enough to compete with coolers in the same price range.


Package contents.

Like previous versions of the CNPS9000 series, the heatsink is packed in a
sturdy plastic clamshell container. The accessories include an instruction sheet,
thermal compound, and mounting hardware. It’s essentially the same package as
the MAX except for the inclusion of a dual fan adapter and hardware for socket
LGA 2011. We frown to see the same installation scheme as the MAX being recycled.
It didn’t produce enough pressure on the base and used very small hexagonal
screws that were hard to secure.

Zalman CNPS9900DF: Key Features
(from the product
web page
)
Feature & Brief
Our Comment
Cross Bending Fin Technology
Front and rear airflow incident angles are designed in different directions. This cross bending fin technology produces cooling performance with minimum noise.
The radial shape of the 9900 pushes exhaust
air out in every direction. One could argue that a standard tower design
directing air toward the case exhaust fan is more effective.
Triple Composite Heatpipes
3 composite heat pipes and pure copper cross bending fins quickly cools down the heat from the CPU.
Not really different than the heatpipes used by other manufacturers.
Dual Fans
Cross Bending ultra quiet powerful 120mm Front Fan and 140mm enter Fan produces top performance.
We’re not crazy about having mismatched
fans &151; they sometimes produce nasty acoustic results.
Blue LED FANS
Beautiful blue LED dual fan.
A must have feature.
Mirroring Base
Zalman’s unique sanding process provides excellent heat transfer ability.
It’s not necessary for a base to have a mirror shine to produce good results.
Fits in Mid Case
With height 160mm and width 180mm it fits in a variety of cases including mid case.
We believe they mean that 160 x 180 mm is the limit for most midsize cases as the 9900DF is much smaller than this.
High compatibility
Compatible with Intel Socket LGA 2011, AMD Socket FM1 and most Intel, AMD platform.
Expected for most performance heatsinks.
ZM-STG2
High performance ZM-STG2 helps to maximize the heat transfer from CPU to CNPS9900DF base allowing optimal cooling performance.
We’ll have to take their word for it. TIM is one of the controls we employ to more accurately compare heatsink performance.
Zalman CNPS9900DF: Specifications
(from the product
web page
)
Dimensions 140(L) x 100(W) x 154(H)mm
Weight850g
MaterialsCopper(base & Fin)
Dissipation Area6,800cm2
Heatpipe Q’ty3EA
Fan SpeedFront 120mm: 1,000rpm ±10% (3pin)
Center 140mm: 900 ~ 1,400rpm ±10%(4pin)
Noise Level19 ~ 27dBA ±10%
Bearing TypeLong Life Bearing
Control Method PWM Control, Auto Restart
Input Voltage12V

PHYSICAL DETAILS

The Zalman CNPS9900DF sports an all copper construction consisting
of a base 3 x 6 mm thick heatpipes and a multitude of very thin fins, all nickel-plated.
By our measurements, the heatsink is 152 mm tall (6.0 inches) and approximately
870 grams (1.9 lb). By modern standards its size is rather conservative.


The core design of the 9900 series remains, though it’s split into two sections each with its own fan. The fins are arranged radially, tightly packed at the center and looser at the edges while the fans disperse the air in every direction.


The DF isn’t much different from the CNPS9900 MAX, The intake portion
of the heatsink has been enlarged to encapsulate a second fan but otherwise
it looks mostly the same. Our biggest complaint, the fan being mounted
on a pair of metal stilts prone to vibration, remains. There’s too much
separation behind the center fan and without a casing, it doesn’t generate
much static pressure.


The thin fan support is freestanding, not anchored to any portion of the heatsink, making it prone to vibration.


The heatsink extends around the edges of the front 120 mm fan while the
sides of the center 140 mm fan are unimpeded.


Though it looks like a six heatpipe cooler, it actually only has three. Each heatpipe is very long, wrapping all the way around the heatsink. In the image above you can see both the thick and thin ends of two of the heatpipes.


The base is a very nice mirror polish but the shape is actually more important
for thermal transfer. The 9900DF’s base is slightly concave; heatsinks
with flat and convex surfaces perform better on the vast majoriity of
heatsinks, which are usually a tiny bit concave. Two concave surfaces
mating againsts each other almost guarantees a gap in the middle. The
gap may be small, in the order of fractions of a millimeter, but the difference
between a gap of any kind versus firm contact is easily 10°C. The
screws on the bottom can be loosened so the metal mounting clips can be
inserted between the base and baseplate, and then re-tightened.

BASE & 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 with the user having to handle as few pieces of
hardware as possible.


The 9900DF employs the same mounting system as its predecessor, the MAX.
For Intel systems, a lug nut is inserted into each corner of the backplate
through the appropriate hole depending on the socket. A plastic brace
goes over it to lock in place for mounting.


Bolts are then used to secure the lug nuts to the clips but because the
heatsink hangs over them, it’s hard to get to. To make it easier, Zalman
uses bolts with shallow hexagonal threads and includes an Allen wrench
in the package. It’s a real pain as the wrench is impeded by board components
like the VRM heatsink, while the long end can only engage the screw head
at an angle. Also note how the mounting clips bend downward, putting most
of the pressure around the perimeter rather than the center of the CPU.


Typically we tightening the bolts down as much as possible to give every
heatsink the best possible chance but we ended up wearing down the hex
head threads easily. We then had to find a different Allen wrench to remove
them which proved to be a major task as the thread size is very small.
Oddly, we didn’t run into this problem with the CNPS9900 MAX despite it
having the exact same system. After re-examining the whole mounting system
and process, both Mike Chin and I concluded that stripping the head threads
of these tiny bolts is more normal than not; we were just lucky that it
didn’t happen with the CNPS9900 MAX… unless those bolts had better threaded
heads.


One nice thing about the 9900DF is it doesn’t take up that much room.
There is about 40 mm of clearance below the bottom fin but the body is
fairly narrow so it didn’t interfering with anything.


An adapter is included to run both fans off a single motherboard fan header
but the larger center fan is a 4-pin PWM model while the front fan is
an old school 3-pin. Using PWM control, the 3-pin fan runs at full speed.

TESTING

Before thermal testing, we took some basic physical measurements.

Approximate Physical Measurements
Weight
870 g
Height152 mm
Fin countA lot
Fin thickness
0.26 mm
Fin spacing
Varies
Vertical Clearance*
40 mm
* measured from the motherboard PCB to
the bottom fin of the heatsink
Large Heatsink Comparison:
Average Fin Thickness & Spacing
Heatsink
Fin Thickness
Fin Spacing
SilverStone Heligon HE02
0.52 mm
3.30 mm
Thermalright HR-01 Plus
0.45 mm
3.15 mm
Thermalright HR-02 Macho
0.34 mm
3.12 mm
Scythe Ninja 3
0.39 mm
2.64 mm
Noctua NH-U12P
0.44 mm
2.63 mm
Noctua NH-C12P
0.47 mm
2.54 mm
Noctua NH-D14
0.43 mm
2.33 mm
Thermalright Archon SB-E
0.49 mm
2.33 mm
GELID Tranquillo Rev.2
0.40 mm
2.30 mm
GELID GX-7 Rev.2
0.31 mm
2.25 mm
Phanteks PH-TC14PE
0.40 mm
2.21 mm
be quiet! Dark Rock 2
0.38 mm
2.22 mm
Prolimatech Armageddon
0.51 mm
2.08 mm
Prolimatech Megahalems
0.50 mm
2.00 mm
Zalman CNPS10X Quiet
0.40 mm
2.00 mm
Scythe Kabuto & Zipang 2
0.34 mm
1.94 mm
NZXT Havik 140
0.41 mm
1.91 mm
Scythe Mugen-2
0.31 mm
1.89 mm
Swiftech Polaris 120
0.43 mm
1.85 mm
Thermalright Venomous X
0.53 mm
1.84 mm
Noctua NH-C14
0.38 mm
1.79 mm
Enermax ETS-T40
0.40 mm
1.79 mm
Scythe Yasya
0.32 mm
1.78 mm
Cogage TRUE Spirit 1366
0.40 mm
1.70 mm
Arctic Cooling Freezer Xtreme Rev.2
0.30 mm
1.70 mm
Scythe Grand Kama Cross
0.38 mm
1.66 mm
Reeven Kelveros
0.47 mm
1.61 mm
Zalman CNPS9900 MAX
0.16 mm
1.59 mm
Thermalright Silver Arrow
0.32 mm
1.57 mm
Cooler Master Hyper 212 Plus
0.43 mm
1.54 mm
Thermalright Ultra-120 eXtreme Rev.C
0.56 mm
1.52 mm
Zalman CNPS10X Extreme
0.42 mm
1.50 mm

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

Key Components in LGA1366 Heatsink Test Platform:

  • Intel Core i7-965 Extreme
    Nehalem core, LGA1366, 3.2GHz, 45nm, 130W TDP.
  • Asus
    P6X58D Premium
    ATX motherboard. X58 chipset.
  • Asus
    EAH3450 Silent
    graphics card.
  • Intel
    X25-M
    80GB 2.5" solid-state drive. Chosen for silence.
  • 3GB QiMonda
    DDR3 memory. 3 x 1GB DDR3-1066 in triple channel.
  • Seasonic X-650 SS-650KM
    650W ATX power supply. This PSU is semi-passively cooled. At the power levels
    of our test platform, its fan does not spin.
  • Arctic Silver
    Lumière
    : Special fast-curing thermal interface material, designed
    specifically for test labs.
  • Noctua 140 mm fan (used when possible with heatsinks that fit 140x25mm
    fans)
  • Nexus 120 mm fan (used when possible with heatsinks that fit 120x25mm
    fans)
  • Nexus 92 mm fan (used when possible with heatsinks that fit 92x25mm
    fans)

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
1250 RPM
28~29 dBA
9V
990 RPM
21 dBA
7V
770 RPM
15~16 dBA
6V
660 RPM
13 dBA
Reference Nexus 120mm fan
Anechoic chamber measurements
Voltage
SPL@1m
Speed
12V
1100 RPM
16 dBA
9V
890 RPM
13 dBA
7V
720 RPM
12 dBA

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

As we mentioned earlier, the fans are attached using metal stands so they lack
the traditional square frame housing found on most case fans. However, the impeller
and blades are similar in size to standard 120/140 mm models. The CNPS9900 MAX
was equipped with a 1600 RPM fan while the CNPS9900DF uses lower speed variants.

Zalman CNPS9900DF: Stock Fan Measurements
Voltage
Speed (Front)
Speed (Center)
Combined SPL@1m
12V
1060 RPM
1370 RPM
32 dBA
9V
870 RPM
1070 RPM
26 dBA
7V
710 RPM
830 RPM
20 dBA
6V
610 RPM
700 RPM
17 dBA
5V
520 RPM
550 RPM
14 dBA
Measuring mic positioned 1m at diagonal angle from
the center of the heatsink.
Ambient noise level: 10~11 dBA.

We’re not crazy about different size fans on one heatsink due to possible intermodulation
effects on noise. It’s also inefficient if each fan’s individual noise output
is significantly different, i.e. one fan drowning out the other when set to
the same voltage/PWM setting. The CNPS9900DF wasn’t bad in this regard despite
a 300 RPM difference at full speed. The center 140 mm model was the faster fan
and thus produced more noise, though subjectively, it sounded better.

At full speed the pair generated a pretty loud 32 dBA@1m but if you’re noise
conscious, the fans can be reduced down to about 14 dBA@1m through voltage control;
the starting voltage was 4.8V and 4.0V for the front and center fan, respectively.

The quality of noise emitted by the 9900DF was simply put, bad. It generated
tonal peaks at multiple frequencies in the 150 to 1,000 Hz range. It made an
unpleasant, harsh drone. At lower speeds, there was also an underlying "wobble"
to the sound, as if one of the fans was off-kilter. This effect was audible
in each individual fan, but particularly in the front model, so it wasn’t a
result of interaction between the two. The overall acoustics were very disappointing
as Zalman’s previous model, the CNPS9900 MAX, actually had a fairly nice sounding
fan for a change.

The cooler’s mismatched fans contributed to the 9900DF’s poor acoustics. Both
fans had noticeable tonality but they also had distinctive noise signatures.
The front fan had a harsher, lower pitch profile, and was the main source of
the aforementioned "wobble" effect. The center fan had a smoother
profile with a higher pitch but it produced a dry, undesirable hum.

Test Results

Zalman CNPS9900DF vs. CNPS9900 MAX
Fan Voltage
CNPS9900DF
CNPS9900 MAX
SPL@1m
°C Rise
°C Rise
SPL@1m
12V
32 dBA
43
41
32~33 dBA
9V
26 dBA
46
42
26~27 dBA
7V
20 dBA
48
45
20 dBA
6V
17 dBA
50
47
16 dBA
5V
14 dBA
53
49
13 dBA
°C Rise: Temperature rise above ambient (22°C)
on load.

To our surprise, the CNPS9900DF turned out to be less proficient than its single fan predecessor, the CNPS9900 MAX. Despite its second fan and larger heat dissipation area, the DF performed 2~4°C worse depending on the fan speed.

The main culprit for its disappointing performance was the heatsink’s concave
base. Despite tightening the cooler to the point that the bolt threads were
almost completely stripped, the thermal compound pattern left behind showed
poor contact, with large tendrils of TIM all over the surface, which only happens
when there are significant air caps between CPU and heatsink base. When good
contact and pressure is achieved, most of the compound is squeezed out toward
the sides; that obviously didn’t happen here.

Heatsink Comparison Tables

CPU Coolers (ref. 120mm fan): °C Rise Comparison
Heatsink
Fan voltage / SPL @1m*
12V
9V
7V
15~17 dBA
12~13 dBA
11~12 dBA
Thermalright Ultra-120 eXtreme Rev.C
38
40
43
Thermalright Venomous X
38
41
43
Prolimatech Megahalems
38
41
44
Noctua NH-U12P
39
42
44
Scythe Mugen-2
39
42
45
Cogage TRUE Spirit 1366
40
42
45
Prolimatech Armageddon
40
42
46
Zalman CNPS10X Quiet
40
43
46
Noctua NH-C14
39
42
48
Scythe Yasya
41
43
47
Thermalright Ultra-120 eXtreme
40
43
48
Cooler Master Hyper 212 Plus
41
44
48
Thermalright Archon SB-E
42
43
49
Thermalright Ultra-120
42
45
49
Titan Fenrir
43
46
50
Scythe Ninja 3
44
47
49
Enermax ETS-T40
44
46
50
Noctua NH-C12P
43
47
51
Zalman CNPS10X Extreme
43
47
53
Swiftech Polaris 120
46
49
54
GELID GX-7 Rev.2
47
50
52
Zalman CNPS10X Flex
45
50
54
be quiet! Dark Rock 2
48
50
52
Cooler Master V8
46
50
54
GELID Tranquillo Rev.2
48
50
53
Reeven Kelveros
47
51
55
Scythe Grand Kama Cross
45
52
57
Zalman CNPS9900DF
(stock fans)
50
53
N/A
17 dBA
14 dBA
Antec Kühler H20 620
(pump at 7V, almost inaudible)
52
52
53
Arctic Cooling Freezer Xtreme Rev.2
49
52
58
Scythe Kabuto
51
53
60
*Note: there are minor differences in measured SPL due to the variety of fan orientations and mounting methods offered by the compared coolers.

Though it has two fans, given its size, we decided not to throw the CNPS9900DF
against top-tier dual fan towers like the recently reviewed Phanteks
PH-TC14PE
. Instead, we mercifully placed in our single 120 mm fan cooler
chart. Even with this lesser field of competition, it came out near the bottom
at similar noise levels to heatsinks paired with our reference Nexus 120 mm
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

Zalman’s signature flower design has gone through a lengthy period of evolution,
upwards of a decade. Compared to its immediate predecessor, the
CNPS9900 MAX
, the main difference is that the CNPS9900DF is larger
and armed with an extra fan. We weren’t impressed with the MAX, and unfortunately,
in the the DF, none of the issues we pointed out in the earlier model were addressed.

Our samples of the CNPS9900 MAX and LED models both had flat bases. The 9900DF
sample, in comparison, has a slightly concave surface that doesn’t make enough
contact with our CPU heatspreader. Concavity in a HS base is an elementary no-no.
This critical error is exacerbated by the lack of pressure supplied by the mounting
system. We did not like it on the MAX, finding it both insufficient and inconvenient,.
This time around, we had severe, hair-pulling difficulty with it. Upon reflection,
it might be one of the worst mounting systems ever devised. The mounting clips
are thin and bend easily, and the use of tiny hex screws that are so difficult
to reach boggles the mind.

The DF is larger than the MAX with more surface area to take advantage of the
added airflow from the second fan but the two fans are different, in size, speed,
and acoustic character — they don’t even use the same connectors! The fans
sound different enough that they don’t drown out each others’ unpleasant characteristics.
Instead they mix together into a muddy symphony of undesirable tones. Some reprieve
can be found at very low fan speeds but at the sacrifice of any appreciable
cooling performance. Being frameless, propped up precariously on two thin metal
legs with no support on the sides doesn’t help the fans at all. (In Zalman’s
defense it might have seemed like a good idea, as it is the same engineering
principle used successfully for decades by real estate agencies and political
campaigns to put up lawn signs.)

We can understand Zalman’s reluctance to abandon the core radial fin design,
and admittedly, they have one of the most attractive lines of heatsinks ever
produced. But the execution has to be so much better than shown by our 9900DF
sample for any chance of competitive success. Each successive flower heatsink
version has used iterative improvements — more surface area, nickel-plating,
a larger fan, a second fan — to improve performance, but without a sensible
execution ensuring all the basic details are well covered, there’s no way this
historic series can compete. For US$90 MSRP, a CPU heatsink must provide
top performance… and if our sample is representatively, the 9900DF doesn’t
even get close.

Our thanks to Zalman
for the CNPS9900DF CPU cooler sample.

* * *

SPCR Articles of Related Interest:

SilverStone Heligon HE02: Monster Fanless CPU Cooler
Prolimatech Panther CPU Cooler
Phanteks PH-TC14PE Dual Fan CPU Heatsink
GELID GX-7 & Tranquillo Rev.2 CPU Coolers
be quiet! Dark Rock 2 Tower Heatsink
Enermax ETS-T40: Direct-Touch Heatpipe Cooler

* * *

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