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Scythe Ninja Mini CPU heatsink

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The Scythe Ninja is an outstanding quiet CPU heatsink. Its simple yet elegant design
takes into account all the factors relevant for quiet cooling: Large surface area, wide fin spacing, multiple heatpipes for even heat distribution through all the fins, and flat, smooth copper base. Of course, not all users can utilize the 150mm tall Ninja or similar tower heatsinks due to the dimensional restrictions of smaller cases. Ergo, the new Ninja Mini.

September 6, 2007 by Lawrence
Lee
[with Mike
Chin
]

Product
Scythe Ninja Mini Model SCMNJ-1000 CPU Heatsink
Manufacturer
Market Price
US$30~45

The Scythe Ninja is one of the most
outstanding CPU heatsinks we’ve
had the pleasure of working with. Its simple yet elegant design
takes into account all the factors that optimize quiet cooling
— large surface area, wide fin spacing, multiple heatpipes for even heat distribution through all the fins, and flat, smooth copper base. Of
course, not all users can utilize the 150mm tall Ninja or similar tower heatsinks
due to the dimensional restrictions of smaller cases.

These were the thoughts going through SPCR editor Mike Chin’s mind as he was working with Antec on the design of the NSK2400/Fusion media PC case. After seeing the first prototype of the case in early 2006, Mike contacted Scythe, asking them to release a short Ninja-style heatsink that would fit within the confines of NSK2400/Fusion. It would have to be no more than ~120mm tall. Mike felt that a high performance heatsink that could be run passively, using the closely-positioned 120mm case fans on the NSK2400/Fusion would sell very well. There were also many other medica PC cases which needed a shorter high performance HS with fins designed for the horizontal (not vertical) airflow best suited for optimized cooling in such cases.

Scythe’s response was lukewarm. A similar product concept had been briefly discussed by key staff, but rejected. They mentioned that the cost savings involved in making a shorter Ninja would be minor, and the smaller size would mean not only smaller fin area but also prevent the use of a 120mm fan. These factors would impact the cooling performance while price would remain pretty close to the original Ninja. Scythe was also unconvinced of the media PC’s popularity among DIY builders, who are naturally the primary market for their products. Even a face-to-face meeting between Mike and Scythe’s product development manager at Computex Taipei in June 2006 failed to get this project started.

Other smaller tower HS with horizonal airflow design have appeared on the market, but none have been ideal for a quiet media PC case. They’ve been a bit too tall, a bit too loud, and/or not quite good enough in cooling performance. So this product niche in CPU coolers remains open.

At the 2007 Computex, some 18 months after Mike first mentioned the idea to Scythe, the company released the Ninja Mini. This product conforms perfectly to Mike’s original requirements: It’s short enough for a 3U height case, uses horizonal airflow configution, and it’s basically a short Ninja. Better late than never. How good a quiet cooler is it? Can it work well without a fan on it in an Antec NSK2400/Fusion case? These are the main questions we’ll seek to answer in this review.

Scythe Ninja Mini Box

As with other Scythe products, the box tries
its
best to be conspicuous.

Scythe Ninja Mini Contents

The cooler has universal support for
current desktop AMD
and Intel sockets including 478. Included are fan clips, a Scythe 80mm
fan, an illustrated installation guide, screws and a package of
thermal compound. A blue plastic protector covers the heatsink base to
prevent accidental scratching and scuffing.

Scythe Ninja Mini
Feature Highlights
(from the product web page)
Feature & Brief Our Comment
Ready for 80mm or 92mm Fan Mounting

The default silent fan (80 x 80 x 25 mm) can be easily exchanged to
another 92mm sized fan with 25mm of thickness for high performance user
(92mm Fan Clips are included).

Due
to its lower
profile, a 120mm fan is inappropriate. A 80 or 92mm fan will have to
suffice. Scythe’s steel wire fan clips are
pretty easy to use.
Improved Mounting Systems

Never stop the improvement of mounting systems, the Ninja Mini CPU
Cooler has the improved mounting mechanism with easier than ever
mounting for all sockets!

The
Ninja
Mini’s AMD
mounting frame is slimmer and less cumbersome than the
original
Ninja’s. The LGA775 mounting scheme has also been streamlined
from
a round frame to a simpler square frame.
Universal Socket Compatibility with AM2

Ninja Mini CPU Cooler is compatible for socket 478/754/939/940/AM2
& LGA775. All in one solution for your PC system.

Three sets of easy to install mounting frames provide
universal socket support.

Scythe Ninja Mini
Specifications
(from the product web page)
Model Number
SCMNJ-1000
Combined Dimensions
110 x 110 x 115 mm
Weight
580g
Compatibility
Intel LGA775 (SocketT) Processors

Intel Socket 478 Processors

AMD Socket AM2 Processors

AMD Socket 940 Processors

AMD Socket 939 Processors

AMD Socket 754 Processors

Fan Dimensions
80 x 80 x 25 mm
Noise Level
24.4 dBA
Air Flow
32.2 CFM
Speed
2,300 RPM (±10%)
Bearing
Type
Sleeve

PHYSICAL DETAILS

Most readers probably want to know what the difference is between the Ninja Mini and the original. The photos below should satisfy your curiosity. (Note: Please ignore the worn condition of the Ninja; it’s our original review sample which has not only survived over two years of abuse in the lab, but also an attempt at height reduction which caused the loss of the end caps of the heatpipes.)


No point for guessing which is which. The height difference is 40mm, or slightly over 1.5", as specified by Scythe.
The family resemblance obvious, but there is a difference in the way the heatpipes are configured. In the Mini, they’re evenly distributed through each fin. This may help improve heat distribution as well as reduce airflow resistance between the fins.

Notice the "auxilary fins" just above the base of the
heatsink in the various photos.
The heatsink is not symmetrical so it is possible to place the
fan in the “wrong” position with the fan blowing against the side of these fins
instead of through them (as pictured
below). This may have some minor impact on CPU cooling, and perhaps in the cooling of other nearby components on the motherboard.

Scythe Ninja Mini Upright When
compared to a tower
heatsink, it’s obvious why it’s called “Mini.” However the name and
picture
is somewhat deceptive – it’s the same width as the original
Ninja. The
Ninja Mini is
primarily composed of 17 large, flat, horizontal aluminum fins
and
6
copper heatpipes running through them. In imperial measurements, it
stands approximately 4.5″ tall and weighs 20 oz.

We also noticed that heatpipes at the
base of the Mini diverge and separate into a well-spaced
clock-like pattern, unlike on the Ninja where the heatpipes
are
packed tightly together. The Mini design allows more air to
pass
between these pipes, especially at the base of the socket where
motherboard components can suffer thermally without top-down airflow.

BASE & MOUNTING CLIPS

Typical of Scythe’s heatsinks, the base is flat, smooth, and polished. This time around, they’ve applied a nickel plating on the copper base, which will keep the copper from tarnishing over time. It’s not clear whether nickel plating has any functional purpose, however; once the HS is installed with thermal goop, it’s not exposed to the oxidation effects of the air.

Scythe Ninja Mini Base

Screw
holes in each corner facilitate installation of the various

mounting frames. This design allows the frames to
be rotated
in freely so
the proper orientation can
always be achieved.

Scythe Ninja Mini S478 Mounting

The S478 mounting
frame. Four hooks are used to grasp onto the S478 plastic
rentention cage.

Scythe Ninja Mini AM2 Mounting

The AMD mounting
frame has metal two latches to hook onto
any A64 retention brackets (AM2/754/939/940).

Scythe Ninja Mini LGA775 Mounting

The LGA775
mounting frame.
Scythe uses the same cylindrical press-fit fasteners found
on Intel’s
stock cooler. We are not fans of the Intel design but with the lower
height and weight of the Mini, it should be adequate.

FAN DETAILS

We hoped Scythe would ship the Ninja Mini with the Scythe Kama Flow 80mm fan (which uses fluid dynamic bearings), but instead they including a
sleeve bearing fan, unknown to us, dubbed the DFS802512L. Being a 3-pin fan, some motherboards featuring 4-pin PWM headers may not be able to control it.

Scythe Ninja Mini Stock Fan

It’s a slow speed sleeve bearing 80x25mm fan..

Stock Fan Specfications:
DFS802512L
Brand Scythe Power Rating 0.09A
Manufacturer ?? Airflow Rating 32.2 CFM
Model Number DFS802512L RPM Rating 2,300RPM
Bearing Type Sleeve Noise Rating 24.4 dBA
Frame Size 80 x 80 x 25 mm Header Type 3-pin

INSTALLATION

Installation of the Scythe Ninja Mini on our LGA775 test
system
was
straightforward. With the four mounting holes being underneath the
edges of the heatsink, we thought there might be problems putting
enough pressure on the fasteners, but luckily this was not the case and
they went in fairly easily. We highly recommend checking the
back of the motherboard to ensure the inner black pins go all
the
way
through; installation inside a case is definitely not a good idea. In any case, once the cylinder fasteners are firmly engaged, the Ninja Mini is quite secure. (Note: The tall column of empty space at
each
corner of the heatsink provides easy
access for a slot screwdriver to release the fasteners for removal.)

Scythe Ninja Mini Mounted
Ninja Mini installed on our 775 socket HS test platform.

Scythe Ninja Mini RAM
A clearance snag.

We ran into a small snag as one of the fan clips
touched the memory
in the first DIMM slot. There
was about a millimeter of clearance when we used the second slot
instead. This may or may not be an issue depending on the
layout of the
motherboard used.

Scythe Ninja Mini NB
Height clearance over our NB heatsink was very good;
without the fan, RAM slots are no problem either.

TESTING

Testing was done according to our
unique heatsink testing methodology
, and the reference fan
was profiled using our standard fan testing methodology.
A quick summary of the components, tools, and procedures follows below.

Key Components in Heatsink Test Platform:

Test Tools

  • Seasonic Power Angel
    for measuring AC power at the wall to ensure that the heat output
    remains consistent.
  • Custom-built, four-channel variable DC power supply,
    used to regulate the fan speed during the test.
  • Bruel & Kjaer (B&K) model 2203
    Sound Level Meter
    . Used to accurately measure noise down to
    20 dBA and below.
  • Various other tools for testing fans, as documented in our
    standard fan testing methodology
    .

Software Tools

  • SpeedFan 4.31,
    used to monitor the on-chip thermal sensor. This sensor is not
    calibrated, so results are not universally applicable; however,
  • CPUBurn P6,
    used to stress the CPU heavily, generating more heat than most
    real applications. Two instances are used to ensure that both cores are
    stressed.
  • Throttlewatch 2.01,
    used to monitor the throttling feature of the CPU to determine when
    overheating occurs.

Noise measurements were made with the fan powered from the lab
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 make sure
that the load temperature was stable for at least ten minutes. The
stock fan was tested at four voltages: 5V, 7V, 9V, and 12V,
representing a full cross-section of the its airflow and noise
performance. It was also tested with our reference 80mm fan, the Nexus 80.

The ambient conditions during testing were 18 dBA and
24°C.

TEST RESULTS

The Stock Scythe Fan

The stock fan was tested to reveal its noise
characteristics. However, we did not measure
airflow as we
are in the process of further improving this aspect of our fan
testing methodology at the moment. We hope to do a more thorough
analysis at a later date.

Stock
Scythe Ninja Mini Fan
(DFS802512L) Measurements
Voltage RPM SPL
12V 2200 28 dBA@1m
9V 1800 22 dBA@1m
7V 1460 19
dBA@1m
5V 1080 <19 dBA@1m
2.5V
(min start)
430 <19
dBA@1m

At 12V, it simply spins a bit too fast to be quiet by SPCR standards, with turbulent noise, a
small a degree of whine and a fair amount of vibration. At 9V the sound
level decreased dramatically but whine and vibration were still evident
with some tonality. At 7V it’s probably quiet enough for the majority
of users though its overall character is unchanged from 9V. At 5V it’s
quiet and smooth with some vibration, and basically inaudible from greater
than 1.5 feet away. We were surprised to find that the
fan started up with only 2.5V though we can’t envision a situation
where such a low voltage would be used. From 5V to 2.5V, the acoustic
difference is negligible from all but the shortest of
distances. Overall it’s a decently smooth fan, a typical
sleeve bearing variety.

Cooling Results

Scythe
Ninja Mini w/ stock 80mm fan
Fan Voltage
Noise @ 1m
Temp
°C Rise
°C/W
12V
28 dBA
43°C
19
0.24
9V
22 dBA
45°C
21
0.27
7V
19 dBA
48°C
24
0.31
5V
<19 dBA
52°C
28
0.36
Scythe Ninja Mini
w/ reference 80mm fan
12V
20 dBA
46°C
22
0.28
9V
~19 dBA
50°C
26
0.33
7V
<18 dBA
55°C
31
0.40
Load Temp: CPUBurn
for ~20 mins.

°C Rise: Temperature rise above
ambient (24°C) at load.

°C/W: based on the amount of
heat dissipated by the CPU (measured 78W); lower is better.

The stock fan was a bit more audible mounted on the Ninja than in free air.
As expected, at 12V, it was unacceptable by our noise standards. It also
made the heatsink “ring” — that is, its fins began to resonate in sympathy
with the fan. Undervolting the fan to 9V brought the noise level down, and the CPU temperature barely rose. Performance was good at all voltage levels with the stock fan.
At 5~7V, the overall balance of cooling and noise seemed about the best: 28°C rise at <19 dBA@1m is pretty darn good when you consider that the CPU is pulling some 70W.

As expected, the Ninja Mini did not do as well with the much quieter reference fan. At
7V °C Rise broke 30°C
and we decided not to proceed any lower. Inside a case where
temperatures are usually significantly higher than out in the open,
it’s unlikely the reference fan could have kept our test CPU
sufficiently cool at 5V. Overall performance was excellent for its size.

With our reference Nexus fan in
this
orientation at 12V, the heatsink’s performance was one
degree worse, so keep
this in mind when placing the fan.

Comparables

Comparisons are limited to the heatsinks tested on our current test platform, which is relatively new. Note that both of the other HS are much larger, and have the benefit of a 120mm Nexus fan which naturally can blow a lot more air for the same level of noise compared to any 80mm fan.

SPL@1m Ninja Mini
(stock fan)
Scythe Ninja
(reference fan)
Thermalright SI-128
(reference fan)
RPM °C
Rise
°C/W RPM °C
Rise
°C/W RPM °C
Rise
°C/W
22
dBA
1800 21 0.27 1080 14 0.18 1080 21 0.27
~19
dBA
1460 24 0.31 850 16 0.21 850 26 0.33
<19
dBA
1080 28 0.36 680 17 0.22 680 29 0.37

The Ninja Mini, despite being hindered by a much smaller fan, is not
left in the dust as one would expect when compared to bigger heatsinks
utilizing 120mm fans. At similar
noise levels, the Mini is outclassed by the original Ninja, but keeps pace with the Thermalright SI-128 (admittedly designed for best performance with higher airflow).

NOISE RECORDINGS IN MP3 FORMAT

Each of these recording starts with five seconds of "silence" to let you hear the ambient
sound of the room, followed by 10 seconds of the fan’s noise at 5V, 7V, 9V and 12V. The five seconds of "silence" is inserted between each 10 second stretch of fan noise to help you remember the reference ambient.

HOW TO LISTEN & COMPARE

These recordings were made
with a high resolution, studio quality, digital recording system, 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. Two recordings of each noise level were made, one from a
distance of one meter, and another from one foot
away.

The one meter recording
is intended to give you an idea of how the subject of this review sound
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. For best results, set your volume control so that the
ambient noise is just barely audible
. 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 one foot recording is
designed to bring out the fine details of the noise. Use this recording
with caution! Although more detailed, it may not represent how the subject
sounds in actual use. It is best to listen to this recording after you
have listened to the one meter recording.

More details about how
we make these recordings can be found in our short article: Audio
Recording Methods Revised
.

IN-CASE TEST RESULTS

We were interested to see how the Ninja Mini would fare in a quiet media PC case; the natural choice was an Antec Fusion. The heatsink testbed was installed into the case without any other peripherals (which were not needed for our thermal/noise testing). Our sample Fusion is a new black version with a 430W version of the SU380 that shipped with the original NSK2400. Antec is transitioning most of the cases with supplied PSUs to the EarthWatts power supplies, so our Fusion sample must be among the last of the older stock. The SU430 has the same acoustics as the SU380, especially at the modest power levels of our test system.

The
only fans used during testing were the one inside the power supply (which has no effect on cooling any other components) and
one of the Antec Tricool 120mm case fans on the low
setting. We chose to jump straight into the deep end of the pool (or more apropos, onto the hot part of the coals): No fan was mounted on the Ninja Mini. A 120mm fan with close proximity
to the heatsink may be as good or even better than a 80mm fan mounted
directly on it. You can see in the photos that the exhaust case fan is so close to the Ninja Mini that it might as well be mounted directly on it.

Ninja Mini in Fusion
The extra 120mm fan vent was blocked off before testing.

We also wanted to see how well the Ninja Mini would perform with the
addition of a video card, so we tested the system
with
both the onboard video and a fanless Geforce 7600GT (GV-NX76T256D-RH)
courtesy of Gigabyte. Note the use of the black plastic baffle just behind the heatsink to direct the intake airflow from the back panel and the top panel of the Fusion over the motherboard VRM and the CPU heatsink before being evacuated by the case fan.

7600GT in Fusion (below)

Fanless Geforce 7600GT graphics card…

7600GT in Fusion (above)

…with cooling fins joined by heatpipes on both sides of the card.

The cooling results were consistently good with just the onboard video or the passive 7600GT.

Test Video Card Temperatures System Power

(AC)

GPU CPU HDD AUX SYS
CPUBurn Onboard

(GMA950)

N/A 55°C 36°C 46°C 38°C 137W
3DMark2006 7600GT 68°C 54°C 36°C 46°C 40°C 140~160W
CPUBurn
+

RTHDRIBL

7600GT 77°C 55~57°C 36°C 46°C 42°C 172W
Temperatures were
taken with SpeedFan and nVidia’s temperature display after
running the testing application(s) for 30 minutes. Ambient temperature
was 24°C.
Testing
applications
used: CPUBurn, 3DMark2006,
RTHDRIBL.

The achieved 54~57°C is very good maximum temperature for an Intel Pentium D950 inside a case, and the
other
temperatures are perfectly benign. (Note: We are not sure
what Speedfan reports as “AUX” and “SYS” temperatures refer to
exactly; suffice it to say they are onboard sensors that Asus considers worth keeping track of). Remember, real media
PC system would never to be pressed this hard for half an hour, nor would
it be powered by a CPU that pulls ~70W on its own. A much cooler mid- to low-end Core 2 Duo or 45W AMD A64X2 are more appropriate CPU choices.

The passively
cooled 7600GT also did quite well inside the case, staying under
80°C during testing. Modern GPUs are known to operate nominally
in
excess of 100°C and nVidia’s throttle point is a
sizzling 115°C. Somewhat surprisingly, adding the 7600GT
only
increased CPU temperature by a marginal amount.

The Antec SU430 power supply was actually the loudest component
in the system, measuring 24~25 dBA @ 1m. The Antec Tricool fan set to low only
produces approximately 19 dBA@1m in free air. The
system
measured 25 dBA@1m directly in front of the case. From the right
side, behind, and directly over it, where the
fans and vents are closer, the noise levels were 1-2 dBA
higher. With a quieter power
supply, a 21-22 dBA system is not out of the question. (Note that the requirements of a media PC are somewhat less demanding than for a home desktop PC, because the sound from TV and movie programming will usually mask any <30 dBA@1m broadband noise from the PC. For more discussion of this issue, see the section ACOUSTICS AROUND A MEDIA PC in
Cases: Basics & Recommendations.


FINAL CONCLUSIONS

The Scythe Ninja Mini performed admirably despite its smaller size and smaller 80mm
fan. Its size allows it to be
mounted in smaller cases where cooling is often a bigger issue than
in a large tower case. It’s dead easy to install on AMD and socket 478 boards, reasonable to install on Intel 775 socket boards, and its modular mounting
system ensures compatibility with almost any current socket motherboard. With its modest price tag, it’s a good value compared to some of the
larger, more dated heatsinks on the market. We could complain that it took too long for Scythe to come up with the Mini, but that’s a throwaway remark. They did more than just reduce the height of the Ninja; we have little doubt that the more even distribution of heatpipes through the fins helps the Mini achieve its high performance.

One
minor disappointment was Scythe’s choice of fan. At full speed the
level of noise was a little too high. We’re used to seeing
much quieter fans included with Scythe heatsinks, so hopefully
this does not become a trend. A 92mm, fluid dynamic
bearing, 4-pin PWM fan compatible with most current motherboard fan controllers would have made us swoon.

The Mini is a very good cooler, even without any consideration of size or fan type used. But there are several situations where a Scythe
Ninja Mini is an excellent choice:

  • You’re
    uncomfortable with the prospect of having a heavy/tall tower
    heatsink inside your system
  • Your case cannot fit the huge high performance CPU heatsinks
  • You
    just want a solid budget CPU cooler
  • You want a perfect passive CPU cooler in an Antec Fusion/NSK2400 or similar media PC case
Pros
* Excellent overall cooling

* Performs well in a low airflow environment

* Can be used in smaller cases

* Easy to install

* 360° mounting frame design
* Excellent AMD & 478 socket mounting clips

Cons
* Non-PWM stock fan could be quieter

* Mounting system for socket 775 could be more secure

Much thanks to Scythe
USA
for the Scythe Ninja Mini sample.

Our thanks also to….

Gigabyte for the excellent Geforce 7600GT GV-NX76T256D-RH graphics card, and to…
Antec for the Black Fusion media PC case.

* * *

Articles of Related Interest

Recommended Heatsinks
SPCR’s unique heatsink testing
methodology

SPCR’s standard fan testing
methodology

Scythe Ninja
Thermalright SI-128
Spire Verticool II

*
* *

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