Scythe Ninja Mini CPU heatsink

Cooling
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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.


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