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.

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.

• Nexus
  120mm Real Silent Case fan at one meter
  — 5V (11 dBA@1m)
  — 7V (12 dBA@1m)
  — 9V (13 dBA@1m)
  — 12V (16 dBA@1m)

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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