• Home
  • blog
  • Scythe SCNJ-1000 Ninja heatsink

Scythe SCNJ-1000 Ninja heatsink

blog image

Scythe’s latest kick at the fanless can is another tall heatpipe heatsink with a loosely spaced fins structure. Unlike the earlier NCU series, which were made only to fit socket 478, the Ninja can be used with all modern desktop CPU platforms. The Ninja, in some ways, is almost conventional by Scythe standards, with no dramatic twists or departures from their previous designs. But it’s bigger. A lot bigger. It may not be the biggest HS you can find in the enthusiast PC cooling market today, but it’s not far off. How does the Scythe Ninja fare in SPCR’s HS torture tests? NOTE: Postscript on Ninja Plus Rev. B (basically the 3rd version) added on Dec 15, 2007

June 17, 2005 by Mike

Scythe SCNJ-1000 Nijna CPU Heatsink
for socket 478 / 754 / 775 / 940 / 939

POSTSCRIPT on Ninja Plus Rev. B (the 3rd version) added Dec 16, 2006 (page 6)

Scythe has been developing large fanless heatsinks that employ heatpipes
for quite some time. Their original NCU-1000 found favor with many silent
PC enthusiasts. The follow-up, the NCU-2000, was an improved version of
the same heatsink.

Their latest kick at the fanless can is another tall heatpipe device with a loosely
spaced fins structure. Unlike the earlier NCU series, which were made only to fit socket 478, the Ninja can be used
with all modern desktop CPU platforms. It is more extreme than anything Scythe
has put out before.

Scythe heatsink designs have always been unique. The Ninja , in some ways, is
almost conventional by Scythe standards, with no dramatic twists or departures
from their previous designs. But it’s bigger. A lot bigger. It may not be the
biggest HS you can find in the enthusiast PC cooling market today, but it’s
not far off.


Unlike many other Scythe heatsinks, Ninja does not appear to be any kind
of play on words.

Model Name: SCNJ-1000 Ninja Heatpipe CPU Cooler
CPU Compatibility: socket 478, 775 and K8
CPU Clock Speed Limit:
This product is not recommended to use with a high CPU frequency under
the fanless mode. If you plan to use this item under fanless mode, your
CPU load should be limited to low-middle loading. For high-end usage,
we recommend to use an optional 120mm fan. Please use this product at
your own risk.
Dimensions: 110 x 110 x 150mm
Weight: 665g
Noise Level: Completely ZERO dB design (in fanless mode)
Optional Fan: 120mm Fan Clip Included (Fan not included)

The “native” clips are for socket 478. The box contains well-thought out
adapters for socket 775 and K8.
There are also clips for a 120mm fan and an assembly sheet.

Feature & Brief Our Comment
2-in-1 CPU Cooler
Ninja cooler is a versatile CPU cooler which supports both fan & fanless
mode! With fan mode, the cooler is ready for the high-end CPU cooling
(with low noise), and with fanless mode, you are in silent mode (noiseless!)
You can get 2 great features in 1 CPU cooler!
We’ll find out.
Great Value Fanless Heatpipe CPU Cooler
For the great performance and total 6x heatpipe, Ninja cooler is the value-for-money
fanless cooler available in the market!
US$50 is competitive.
Light Weight Fanless CPU Cooler
With the given performance level and size of the heatsink, the Ninja cooler
is lightweight fanless cooler available in the market!
It is light for the size.
A lot of the weight is at the base, minimizing the cantilever stress effect
on a vertically installed motherboard.
Easy Installation-Just One Clip
Easy one clip and screwless design for the quick and easiest installation
ever! (for socket 478)
True only for socket 478.
The others need adapters and access to both sides of the motherboard.

Here is the Ninja, on its side.

There are a total of 12 copper heatpipes that come up from the
copper base. Scythe describes it as 6 heatpipes; presumably they are U-shaped.
Whether it is 6 or 12 is a moot point: There are 12 heatpipe lengths
which wick the heat away from the base up into the aluminum fins. There are
24 aluminum fins in total, well spaced for good airflow even at slow rates.
Any tighter, and fanless operation would not be possible because of the impedance
to airflow.

You will notice two rows of notches along the edges of the fins,
on each face. It’s easier to see than to explain, in the photos and above. These
notches are meant to act as hooks for wire clips that can hold a 120x25mm fan
against any side.

View from top. Note two notches on each side, for a total of eight on each

Fan clipped on one side…

…from another angle.

The deep notches that extend in from each corner of each aluminum
fin are worthy of note. They are there to help reduce airflow impedance. This
is important because of the large dimensions of each fin. It is difficult for
air to flow more than a couple of inches through a restricted space, especially
when the static pressure of the fan is low, as would be the case when a fan
is spinning slowly or only rising air from convection is employed.

Note that the wire clips hook the fan and press it up against the edges of the finds to keep it in place. This means that the fan can only be mounted with its central frame against the fins, blowing into the HS rather than sucking out.

On many motherboards, mounting the fan to blow across the HS and out towards the back panel vent or fan means the fan’s bottom edge must sit atop the first bank of memory sticks. It may require than the fan’s vertical position vis-a-vis the HS be adjusted so that it sits a little higher than pictured above. This is easily achieved, as the wire hoots are quite versatile, if a bit flimsy. The wire does not have to catch on every HS fin notch, which is how you can position the fan to clear the memory. In practice, no problems were encountered just letting the bottom of the fan rest on the top edge of the memory.

The smoothness and flatness of the base was excellent, calling to mind the
best of the Swiftech, Zalman and Alpha HS products.

Smooth flat copper base.

In case there is any question of size… Clockwise, from left:
Scythe Ninja , Scythe NCU-1000, Zalman 7000, Arctic Cooling Freezer, Thermalright
XP120, stock Intel HSF. And standard size mouse.

Another view of the bits & pieces. The metal parts for socket 775
are exceptionally nice.
Much better than the similar plastic parts for the Thermalright XP-120.

Unidirectional Airflow Design

A notable aspect of the Ninja design is that unlike all the other tall, horizontal airflow heatsinks, it allows for a fan to be mounted blowing up or across regardless of motherboard type or how the HS mounting frame on the motherboard is configured. With all the other tall tower heatsinks I am aware of, this is not the case. The airflow directionality of the heatsink is fixed, usually because the fins are open on only two of the four sides. This means that the direction of the airflow is fixed, and it is entirely dependent on the configuration of the motherboard’s heatsink mounting frame. The CoolerMaster Hyper 6 or the Scythe FCS-50 are examples of this type of limitation. In the Scythe NCU (1000, 2000 and 2005) series, the base can be separated and rotated to change the directionality of the airflow through the heatsink, but this is a more complication solution to the problem.


The unit was installed on SPCR’s socket 478 testing motherboard
in under a minute without tools. This is despite the board not being particularly
friendly for big HS. The Thermalright XP120, the Zalman 7000/7700, Scythe’s
earlier models ? all were more trouble to get on. The Ninja was much easier.

Easy to install despite the large size.

It was also installed on an Intel 775 board, pictures of which
are missing, but again, the installation process was straightforward and painless
once the 478-adapter brackets were mounted. The board had to be out of the case
for the adapter brackets, because you need access to the underside of the board,
but this is true for most of the other performance HS, too. Getting the brackets
on was easy.

It is advisable to keep the motherboard out of the case until
the HS is fully installed, because access all around the HS is needed, and it’s
easier without being hampered by the confines of the case. This is true for
most big HS.

Although I have not tried using the aforementioned large heatsinks
on a large number of motherboards, my impression is that the Ninja wins hands
down for ease and safety of installation on both 478 and 775 sockets. There’s
no reason to think it would not be the same for K8. The tension on the clips
is not so awkwardly (dangerously?) high as in the Thermalright XP120, and despite
its large size, the clearance near the base of the Ninja is excellent. Unless
you have a very restrictive motherboard, the Ninja should be a fairly safe and straightforward


Test Platform

  • Intel
    The Thermal Design Power of this P4-2.8 (533
    MHz bus) is 68.4 or 69.7W depending on the version. As the CPU is a demo model
    without normal markings, it’s not clear which version it is, so we’ll round
    the number off to ~69W. The Maximum Power, as calculated by
    & CPUMSR
    , is 79W.
  • AOpen
    AX4GE Max
    motherboard – Intel 845GE Chipset; built-in VGA. The on-die
    CPU thermal diode monitoring system reads 2°C too high, so all readings
    are compensated up by this amount.
  • OCZ DDRAM PC-3700, 512 MB
  • Seagate Barracuda IV 40G 1-platter drive (in Smart
    from Silicon
  • Seasonic
    Super Tornado 300
    (Rev. A1)
  • Arctic Silver
    Thermal Compound
  • Nexus 120 fan
  • Two-level plywood platform with foam damping feet. Motherboard on
    top; most other components below. Eases heatsink changes and setup.

Measurement & Analysis Tools

The ambient temperature during testing was 21°C. Ambient noise level for
testing and recording was 18 dBA/1m.


Scythe Ninja w/ Nexus 120
Fan V / CFM
Load Temp
°C Rise
no fan
12V / 42
22 dBA/1m
9V / 36
<19 dBA/1m
7V / 28
<17 dBA/1m?
Load Temp: CPUBurn for ~20 mins.
°C Rise: Temperature rise above ambient at load.
°C/W MP / TDP: Temperature rise per Watt, based on CPU’s
Maximum Power (79W) or Thermal Design Power (69W) rating
Noise: SPL measured in dBA at 1m distance with high accuracy

No fan: Without a fan, and with the motherboard sitting horizontal on
the test bench, the CPU hit >70°C in 20 minutes and the system froze
at some point beyond that. This might seem an instant dismissal of Scythe’s
claims about the Ninja being an effective fanless heatsink, but it really is
not. The Ninja will do better with the motherboard oriented vertically so that
its fins are running perpendicular to level.

There was no time to repeat the fanless test with the motherboard vertical,
as this review process clashed with hectic preparations for the trip to Taipei
for Computex 2005.

Inside a real system, there would be nearby airflow from
an exhaust case fan and/or a power supply. The assumption of peripheral airflow
is the basis of all heatsinks marketed as “fanless”. Either that or
a <20W CPU, preferably <10W. Given the good experience many users have
had in real systems with the smaller NCU-1000 & 2000 from Scythe, I’d say that careful, sophisticated users should have good results with a fanless
Ninja . Just how hot a CPU the Ninja can cool without a fan mounted directly on it will depend greatly on airflow around it.

Nexus 120 – 12V / 42 CFM: At full tilt, this fan blows slightly above
40 CFM, which is modest for a 120mm fan. It’s also very quiet and smooth, by
a small margin, the quietest fan encountered in SPCR testing. The 14°C rise
is on par with the performance of the Thermalright XP120 in our review, using
fans that blow a bit more air than the Nexus 120. This puts the Ninja at the very top of
our current heatsink performance chart.

Nexus 120 – 9V / 36 CFM: The fan is audibly quieter, and the Ninja cooled
at almost the same level of performance as when the fan was at 12V. A 16°C rise is great for this low
level of noise.

Nexus 120 – 7V / 28 CFM: At this speed, the Nexus fan is inaudible
from a meter away even in the very quiet test room. Inside a PC case, it would
be inaudible under almost all conditions. The 28 CFM is with very low pressure,
yet the cooling performance remains tops; 0.27 °C rise per watt is still
excellent even for today’s super hot CPUs.


Scythe Ninja HS with Nexus 120 fan:

MP3: Nexus 120 – 8.8V – 35 CFM / 19 dBA @ 1m

MP3: Nexus 120 – 12V – 41 CFM / 22.5 dBA @ 1m

Recordings of Comparable HSF:

MP3: Arctic
Cooling Super Silent 4 Ultra TC MP3, 22 dBA/1m

MP3: Zalman 7000 – 5V – 22 dBA/1m

MP3: Panaflo 80L – 7V – 17 dBA/1m — on most any heatsink

MP3: Coolermaster Hyper 48 – 9V – 21 dBA/1m


These recordings were made with a high
resolution studio quality digital recording system. The microphone was 3″ from
the edge of the fan frame at a 45° angle, facing the intake side of the fan to
avoid direct wind noise. The ambient noise during all recordings was 18 dBA or
lower. It is best to download the sound files to your computer before listening.

To set the volume to a realistic level (similar to the original), try playing this Nexus 92mm case fan @ 5V (17 dBA/1m) recording and set the volume so that it is barely audible. Then don’t reset the volume and play the other sound files. Of course, all tone controls and other effects should be turned off or set to neutral. For full details on how to calibrate your sound system playback level to get the most valid listening comparison, please see the yellow text box entitled Listen to
the Fans
on page four of the article
SPCR’s Test / Sound Lab: A Short Tour.


The Scythe Ninja has been used extensively in testing of the Antec P180 case. Consider the juxtaposition of the heatsink relative to the two exhaust 120mm fans on the P180:

On this motherboard, the Ninja is about 1″ away from both top and back 120mm
exhaust fans in an Antec P180 case.
If desired or needed, a 120mm fan can be mounted on the Ninja to blow upwards
or to blow backwards.
Either would result in a dual-fan push-pull airflow configuration.

Much of the testing for the P180 was conducted with an Intel 670 processor (P4-3.8, Prescott), arguably one of the hottest desktop CPU ever made, with a Thermal Design Power rating of 115W and a potential Maximum Power of 158W. With ambient room temperature varying 22~25°C, the Ninja was operated without a fan directly on the unit (as shown above) with both the P180 case fans running at minimum speed. Stress testing with CPUBurn resulted in temps no higher than ~60°C. When only one of the case fans was used, the CPU temp rose to ~67°C, with thermal throttling occurring about 5% of the time. Increasing the speed of the Antec P180 case fan (Tri-Cool 120x25mm) to the mid-setting brought the temp down to ~60°C again.

The push-pull configuration mentioned above was not tried prior to this review, but it seemed unnecessary given the stellar performance of the Ninja even with just the P180’s case fans.


The cooling performance of the Ninja Scythe is the best we’ve reviewed. At the relatively modest airflow of the Nexus 120 fan at 12V or at the low airflow of the same fan at 7V, the Ninja is right in step with the XP-120, which was tested with a slightly higher airflow fan.

The Ninja also has two other advantages that make it a better product:

  • It is far easier to mount than the XP-120, on any of the three major processor sockets currently in use: 478, 775 or K8. We’ve always maintained that ease of correct installation is an integral, important part of the success of any aftermarket heatsink. The tension on the clips is not low, but it does not require the bite-on-a-bullet-and-sweat pressure of the XP-120’s clips to be engaged. It also clears taller components mounted around the CPU socket more easily than the XP-120. These traits mean better user-friendliness and higher usability with a wider range of motherboards.
  • It is set up for across-the-board airflow, which is the preferred airflow direction for the best case airflow management. A 120mm fan on the Ninja can work perfectly in push-pull conjunction with a 120mm exhaust fan mounted on many mid-tower cases.

My final assessment should be obvious: The Scythe Ninja is an excellent HS that can be confidently recommended for the most demanding CPU cooling challenges at truly whisper quiet noise levels when mated with the correct 120mm fan. Overclockers will be delighted with the Ninja as well; with even moderate airflow it should be able to tackle all manner of hot processors. In the right case, like an Antec P180, the Scythe Ninja is just about perfect.

* Great cooling performance with a wide range of airflow
* Universal mounting system ensures very good compatibility
* Highly efficient design
* Across-the-board fan airflow
* Unidirectional airflow design
* Potential to use without direct fan cooling

* Low turbulence design (for minimum noise)
* Modest mass and good weight distribution

* Not ideal for fanless cooling in horizontal case
* Too big for some cases
* Tight fit on some motherboards
* Fan mounting slightly tricky

Much thanks to Scythe
for the Ninja sample.

* * *

POSTSCRIPT, Dec 16, 2007: Scythe Ninja, version 3 (overleaf, on page 6)

Comment on this article in our Forums.


Dec 16, 2006 by Kelly

The original Scythe SCNJ-1000 Ninja heatsink has proven to be one of the most
popular enthusiast heatsinks available. It is one of the best heatsinks that
we have reviewed at SPCR in terms of cooling and potential for quiet operation.

The recently released Scythe SCNJ-1100P, also known as the Ninja Plus Rev.
B, is the third version of the Ninja. This version is very similar to the previous
version except for the mounting system. Now included are a Scythe branded fan,
a redesigned mounting bracket for the LGA775 socket, and a new bracket for the
AM2 socket.

Scythe’s Ninja Plus Rev. B with LGA775 Adapter Attached.

The cooling provided by the Ninja has not changed; it is still one of the best
heatsinks on the market. The basic design of the Ninja remains: Twelve heatpipes
running through a stack of large, thin, widely spaced aluminum fins. The fin
spacing is very similar, but the previous revision had a fairly big notch in
the corners of the bottom fins for the built in native socket 479 clips, as
shown in the photo below.

The weight of the new Ninja is 640g without the attached fan. The weight is
mainly in the base and should not be a major concern if mounted correctly.

While the Ninja now has support for all modern desktop processor sockets, there
have been a number of compatibility reports with the LGA775 and AM2 adapters;
check with the compatibility data provided on Scythe
to confirm that this version will fit on your motherboard. The LGA775
mounting adapter can interfere with the VRM’s of certain motherboards, and the
AM2 adapter has also been shown to block some of the RAM slots.

When mounting, the easiest and safest method is to mount the Ninja on the motherboard
outside of the case. This is especially true for the LGA775 adapter where you
will need to make sure that the push-pins have been fully inserted and locked.
The push-pins are awkwardly placed under the fins and inserting them correctly
takes a considerable amount of force and dexterity. If the notches in the corners
of the earlier version Ninja had been retained, inserting and locking the push-pins
would be much simpler. A visual inspection of the push-pins on the underside
of the board is required to ensure that the Ninja is secured in place.

An LGA775 adapter push-pin when fully inserted.

The Scythe fan included with the SPCR sample was a Scythe DFS122512L. This
fan appears to be of medium quality, but does not fit the noise specification
given on the Scythe website (Ninja
and fan).
The included fan has a slight buzzing sound at 12V, but is relatively quiet
when undervolted. While the specifications are not exactly the same, the noise
produced from this fan is very similar to the Scythe Kama Flow fan that we recently

Overall this is a welcome revision to the Ninja heatsink; now the Ninja has
support for all modern desktop sockets. The Ninja is still one of the best available
heatsinks on the market. Cooling is superb, and with the included fan noise
is acceptable. To ensure the quietest operation though, undervolt the fan to
achieve near silent operation.

Comment on this article in our Forums.

Leave a Comment

Your email address will not be published. Required fields are marked *