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Zalman CNPS10X Flex CPU Cooler

zThe Zalman CNPS10X Flex is a humbler, cheaper version of the CNPS10X Extreme. It lacks the nickel-plating, extravagant fan controller, and stock fan of the Extreme, but has an improved mounting system and steps have been taken to accommodate an extra fan.

February 14, 2010 by Lawrence Lee

Product
Zalman CNPS10X Flex
CPU Cooler
Manufacturer
Zalman
Street Price
US$45~$55

Last summer, after years of banking on the radial heatsink design made famous
in their CNPS7000 series of CPU coolers, Zalman finally put out a conventional
tower style heatsink, the CNPS10X
Extreme
. Its release brought Zalman back in competition with high performance
heatsink makers like Thermalright, Noctua, and Scythe. However its cooling proficiency
was decidedly unimpressive compared to the best coolers of today, particularly
when paired with a low speed fan which is an important requirement for silent/quiet
computing. Its lackluster performance combined with the high price-tag makes
its competitors far more desirable.


The box.

The CNPS10X Flex is more affordable, being a simpler version of the Extreme.
The nickel-plating, extravagant fan controller, and stock fan with a custom
housing did little to improve the actual performance of the Extreme and are
noticeably absent on the Flex. The heatsink structure is basically the same,
though the surface design has been altered somewhat, and accommodations have
been made on the back side for a second fan. The mounting system has been improved
as well, with a single multi-socket backplate; there is no plastic mount hardware
this time around. It will be interesting to see if these changes will result
in more effective cooling.


Package contents include a mult-socket backplate, anti-vibration strips,
and four wire fan clips.

 

Zalman CNPS10X Flex: Key Features
(from the product
web page
)
Feature & Brief
Our Comment
Dual Fan Support
The heatsink is designed to accommodate one or two fans according to the
user’s preference.
As the CNPS10X series has tightly spaced
fins and is wider than most heatsinks, an extra fan would certainly be beneficial.
Powerful Cooling Performance

Optimally designed aluminum fins disperse heat away from the CPU via 5 heatpipes,
while the high capacity 120mm fan quickly cools the heatsink for stable
operation of high performance CPUs.

Remains to be seen.
180mm Wide Case Compatibility
For optimum case compatibility the heatsink’s height is set to 151mm,
ensuring compatibility with 180mm width cases.
151mm puts it about 10mm shorter than
the tallest tower heatsinks.
Differentiated Design
Differentiated from typical U-shaped heatpipe coolers, a central band of
black anodized fins adds a sleek and cool aesthetic finish.
The black stripe is distinguishable,
but hardly practical. Listing this as a major feature is reaching.
High Performance Super Thermal Grease
ZM-STG2

New high performance thermal grease ZM-STG2 maximizes heat transfer from
the CPU to the base of CNPS10X FLEX for intensified cooling performance.
In our experience, most TIMs perform
very closely to one another.
Versatile Compatibility
CNPS10X Flex accommodates a broad range of sockets.
Intel LGA1156/1366/775, AMD AM3/AM2+/AM2/754/939/940
We applaud Zalman for implementing a
hard mounting system for all sockets.

 

Zalman CNPS10X Flex: Specifications
(from the product
web page
)
Dimensions 133(L) X 74(W) X 151(H)mm
Weight 700g
Materials Fins: Aluminum / Base: Copper
Dissipation Area 8,200cm2
Heatpipes 5 U-shaped heatpipes
Compatibility List
Intel LGA1156 Core i7
Core i5
Core i3
LGA1366 Core i7
LGA775 Core 2 Quad
Core 2 Duo
Core 2 Extreme
Pentium Dual Core
Pentium D
Pentium 4
Celeron D
AMD
AM3 Phenom II
Athlon II
AM2+ Phenom II
Phenom
Athlon FX, Athlon 64 FX
Athlon X2, Athlon 64 X2
Athlon, Athlon 64
Sempron
AM2 Athlon FX, Athlon 64 FX
Athlon X2, Athlon 64 X2
Athlon, Athlon 64
Sempron
940 Dual-Core Opteron
Opteron
Athlon FX, Athlon 64 FX
939 Dual-Core Opteron
Opteron
Athlon FX, Athlon 64 FX
Athlon X2, Athlon 64 X2
Athlon, Athlon 64
754 Athlon, Athlon 64
Sempron

PHYSICAL DETAILS

The heatsink features five “U” shaped copper heatpipes
in staggered array and 53 fins. It is designed to be cooled by either one or
two 120mm fans.


The Flex has a distinct black band of anodized fins at the center, making
it easily recognizable. The fins are 0.40mm thick and spaced 1.50mm apart
on average, very tight for a CPU heatsink.


A black plastic cover resides on the top of the cooler. The two main surfaces
are dissimilar, one being noticeably wavy while the other is more flat.
Pictures on Zalman’s product page show a single fan mounted on the wavy
side, but nothing in the literature suggests that one side is superior
to the other.


Zalman also provides black rubber isolation strips for the fan(s), following
in the footsteps of Noctua and Thermalright. It’s obvious they’ve placed
an emphasis on keeping the fan from being flush with the main heatsink
body.


The Flex is a more plain heatsink compared to the Extreme, lacking the
nickel plating on the fins, heatpipes and base.

BASE & INSTALLATION

The most critical aspect of installation is for the heatsink
to be securely mounted. The more firmly it is installed, the better the contact
between the heatsink’s base and the CPU itself. It’s also less likely to fall
off. Ease of installation is also important — a simple mounting scheme
means less time spent installing, and a reduced likelihood of screwing up.


The Flex features a hard mounting system which is compatible
with all of AMD and Intel’s current sockets. To prep the backplate,
four nuts are inserted into the appropriate holes, and plastic covers
are slipped over them to lock them into place.


A piece of double-sided tape is used immobilize the backplate during
mounting.


The four screws holding the mounting plate to the base are loosened
so a pair of mounting clips can be slipped in and secured. Note that
for AMD installation, the clips run parallel with the fan(s), so the
Flex will be in the ‘proper’ orientation, blowing toward the I/O shield.


The mount is finished using four bolts on the topside, resulting in
a solid mating.


Installed on our Asus P6T SE motherboard with our reference Nexus 120mm
fan.

TESTING

Before thermal testing, we took some basic physical measurements.

Zalman CNPS10X Flex:
Approximate Physical Measurements
Weight
700 g
720 g with topside mounting hardware
Fin count 53
Fin thickness
0.40 mm
Fin spacing
1.90 mm
Vertical Clearance
45 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)

A comparison of fin thickness and spacing among various tower heatsinks is
interesting. The Flex has medium sized fins compared to most tower coolers,
but they are spaced very tightly, similar to the Thermalright Ultra-120 series.

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
Thermolab Baram
0.44 mm
2.52 mm
Noctua NH-D14
0.43 mm
2.33 mm
Prolimatech Megahalems
0.50 mm
2.00 mm
Xigmatek HDT-S1283
0.33 mm
1.96 mm
Scythe Kabuto & Zipang 2
0.34 mm
1.94 mm
Scythe Mugen-2
0.31 mm
1.89 mm
ZEROtherm Nirvana
0.43 mm
1.82 mm
ZEROtherm Zen
0.37 mm
1.80 mm
Zalman CNPS10X Flex
0.40 mm
1.50 mm
Zalman CNPS10X Extreme
0.42 mm
1.50 mm
Thermalright Ultra-120
0.45 mm
1.42 mm

Testing was done on our new
i7-1366 heatsink testing platform
. A summary of the test system and
procedure follows.

Key Components in Heatsink Test Platform:

  • Intel Core i7-965 Extreme
    Nehalem core, LGA1366, 3.2GHz, 45nm, 130W TDP.
  • Asus
    P6T SE
    ATX motherboard. A LGA1366 X58 chipset board with short solid-state
    capacitors around the CPU socket, low profile northbridge and VRM heatsinks,
    and mounting holes for both LGA1366 and LGA775 coolers.
  • Asus
    EAH3450 Silent
    graphics card.
  • Intel
    X25-M
    80GB 2.5″ solid-state drive. Chosen for silence.
  • 2GB QiMonda
    DDR3 memory. 2 x 1GB DDR3-1066.
  • 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.
  • Nexus 120 fan (part of our standard testing methodology; used when
    possible with heatsinks that fit 120x25mm fans)

The system is silent under the test conditions, except for the CPU cooling
fan(s). The CPU/system is run in two modes:

  • Default – using all the stock settings in the BIOS. The AC power
    drawn by the system is 165~175W, depending on how well the CPU is cooled.
    When the CPU runs hotter, so does the Voltage Regulator Module on the motherboard
    which powers the CPU, and it becomes less efficient, causing higher system
    power consumption.
  • Overclocked – to 3.6 GHz, 1.4V vCore. This is to simulate typical/extreme
    overclocking by an enthusiast/gamer. The increased core voltage is the source
    of most of the increased power draw. The AC power of the system measures 215~245W,
    depending on how hot the CPU/VRM is allowed to run.

There is no way for us to accurately determine the power drawn by the CPU.
It is extremely difficult to isolate the CPU’s power because the i7-1366 draws
power from both the AUX12V socket as well as the +5V and +3.3V lines on the
mainboard. We can only guesstimate it to be at least 110W in default mode, and
perhaps ~160W at our overclocked setting.

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
5V
11 dBA
530 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 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; throttling
    has been observed to occur at between 95~100°C.
  • 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 20~21°C.



TEST RESULTS

Cooling Results

Zalman CNPS10X Flex w/ reference 120mm fan
(Default)
Fan Voltage
SPL@1m
Temp
°C Rise
12V
16 dBA
62°C
42
9V
13 dBA
65°C
45
7V
12 dBA
69°C
49
Zalman CNPS10X Flex w/ reference 120mm fan
(Overclocked @ 3.6GHz, 1.40V)
12V
16 dBA
76°C
56
9V
13 dBA
85°C
65
7V
12 dBA
91°C
71
Load Temp: Prime95 for ~10 mins.
°C Rise: Temperature rise above ambient (20°C) at load.

The Flex had little difficulty keeping our i7-965 cool, even with our low speed
reference fan. At 12V, the fan is quiet, and the highest core temperature was
42°C above ambient. At 7V, the fan is basically silent yet the temperature
increased by only 7°C. Its effectiveness obviously took a tumble on our
overclocked/overvolted platform, coming close to failing with the fan at 7V
with a temperature of 91°C. Our CPU throttles when a core reaches about
95°C.

Comparables

°C rise Comparison: i7-965 @ default settings
Heatsink
Nexus 120mm fan voltage /
SPL @1m
i7-965 Rank
12V
9V
7V
16 dBA
13 dBA
12 dBA
Noctua NH-D14
36
38
41
#1
Prolimatech Megahalems
35
39
42
#1
Scythe Mugen-2
37
40
43
#3
Noctua NH-U12P
38
40
41
#3
Thermalright U120 eXtreme
38
41
45
#5
Zalman CNPS10X
Extreme
39
43
48
#6
Thermalright U120
42
44
49
#7
Zalman CNPS10X Flex
42
45
49
#7
Scythe Kabuto
43
48
54
#9
Noctua NH-C12P
44
47
54
#9

With our CPU at stock settings, the Flex, despite it’s superior mounting scheme,
failed to surpass the Extreme,
trailing by 3°C at 12V, 2°C at 9V, and only a single degree at 7°C.
It tied for 7th spot with the Thermalright Ultra-120, about 7°C worse than
the top contenders, the Prolimatech
Megahalems
and Noctua NH-D14.

°C rise Comparison: i7-965 @ 3.6GHz, 1.40V
Heatsink
Nexus 120mm fan voltage /
SPL @1m
i7-965 OC Rank
12V
9V
7V
16 dBA
13 dBA
12 dBA
Noctua NH-D14
45
52
57
#1
Prolimatech Megahalems
50
53
59
#2
Thermalright U120 eXtreme
51
56
63
#3
Noctua NH-U12P
53
56
60
#4
Scythe Mugen-2
53
56
62
#4
Thermalright U120
56
60
67
#6
Zalman CNPS10X Flex
56
65
71
#7
Zalman CNPS10X Extreme
60
66
FAIL
#8
Scythe Kabuto
62
70
FAIL
#9
Noctua NH-C12P
64
73
FAIL
#10

On our overclocked platform, the Flex was more than 10°C behind the leading
NH-D14, with the gap widening as the fan speed was reduced. When the heat was
turned up, the Flex did manage to outpace the Extreme, besting it by 4°C
at 12V and preventing the processor from throttling when the fan was set to
7V, something the Extreme failed to do. The narrow fin separation is undoubtedly
the culprit for its comparatively low performance, though it should be noted
that Thermalright’s Ultra-120 series copes much better despite having similar
fin spacing. It would seem from these results that the Flex is better complimented
by a either two fans, or a single high airflow fan.



Dual Fan Performance

°C rise Comparison: i7-965 @ 3.6GHz, 1.40V
Heatsink
Nexus 120mm fan voltage /
SPL @1m
12V
9V
7V
16 dBA
13 dBA
12 dBA
Noctua NH-D14
(two fans)
44
46
49
19 dBA
14 dBA
12 dBA
Noctua NH-D14
45
52
57
Prolimatech Megahalems
50
53
59
Zalman CNPS10X Flex
(two fans)
51
55
59
20 dBA
14 dBA
12 dBA
Thermalright U120 eXtreme
51
56
63
Noctua NH-U12P
53
56
60
Scythe Mugen-2
53
56
62
Thermalright U120
56
60
67
Zalman CNPS10X Flex
56
65
71

Adding a second Nexus 120mm fan to the Flex improved its cooling capacity dramatically,
especially at the 9V and 7V levels, with an increase in performance of 10°C+.
At 7V, it goes from being close to thermal failure to a top 3 contender. However,
it’s sad that with a second fan and of course higher noise levels, the Flex
still fails short of the Megahalems with a single 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

The Zalman CNPS10X Flex has some inherent advantages over the more extravagant
CNPS10X Extreme. It sports
a lower price-tag thanks to its lack of the Extreme’s nickel coating, fan controller
and loud stock fan. In addition, the mounting system has gone through a much
needed overhaul. The Extreme ships with a several sets of mounting hardware
to accommodate the different CPU sockets, lacks a backplate for LGA1366, and
points the fan upward on AMD boards. The Flex on the other hand has a single
backplate with a clever design that supports every modern socket, and on AMD
platforms, the fan blows toward the side.

Despite the improved mounting scheme, the Flex failed to best the Extreme when
it came to thermal performance. It was slightly less effective cooling our i7
processor at stock settings and just edged it out when we heated it up through
overclocking/overvolting; in essence, the battle ended in a draw. Compared to
the majority of tower heatsinks we’ve tested previously, they both delivered
middling performance with our low airflow fan at full speed. When the fan was
slowed down, things got ugly, with the Flex narrowly avoiding the CPU throttling
experienced by the Extreme. With the heatsink being fairly deep and its fins
so tightly spaced, a second fan or a single, higher speed fan is required to
get the Flex to outshine top tier heatsinks.

That being said, the Flex is far from a terrible CPU cooler, after all it only
trailed the best tower heatsinks by about 7°C when tasked with cooling a
130W Core i7. It is easily capable of adequately cooling all modern desktop
processors at stock speeds, even quietly with the right fan. Also, it can be
found online for as low as $45, cheaper than most of the high-end coolers on
the market.

Zalman CNPS10X Flex
PROS

* Simple and secure multi-socket mounting system
* AMD mounts in the “proper” orientation
* Good high airflow performance

CONS

* Poor low airflow performance

Our thanks to Zalman
for the Zalman CNPS10X Flex heatsink sample.

* * *

Articles of Related Interest


Noctua NH-D14 flagship dual-fan CPU
cooler

SPCR’s 2010 CPU Heatsink
Test Platform

Scythe Top-Down Coolers:
Kabuto vs. Zipang 2

Scythe Mugen-2 CPU Cooler
CNPS10X Extreme: Zalman’s Extreme Makeover
Prolima Megahalems: A Mega Nehalem
Cooler

* * *

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