Scythe Andy Samurai Master CPU heatsink/fan

Cooling
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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 that most realistic loads. 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 fan was tested at four voltages: 5V, 7V, 9V, and 12V, representing a full cross-section of the its airflow and noise performance.

The ambient conditions during testing were 18 dBA and 22°C.

TEST RESULTS

The Fan

The stock fan is the same model supplied with the Infinity. We found the earlier sample to be one of the quietest stock heatsink fans ever, and similar to our reference fan. This second sample was just about identical to the first.

Unlike the sample that came with the Infinity, this sample displayed no audible clicking or chuffing at any angle or speed. We had suspected the earlier sample was damaged; our experience with this sample confirms the suspicion. At the same CFM, the Scythe and the reference fan sounded just about identical, and they performed identically with the Andy on the test bench.

Stock Fan Profile: Scythe DFS122512
Brand Scythe Power Rating 0.18A
Manufacturer ?? Airflow Rating 49.58 CFM
Model Number TT-1225 RPM Rating 1,200 ± 10% RPM
Bearing Type Sleeve Noise Rating 20.94 dBA
Hub Size 1.59" Header Type 3-pin
Frame Size 120 x 120 x 25 mm Starting Voltage 4.6V
Voltage
Noise
RPM
CFM
Power
12V
24 dBA@1m
1200 RPM
54 CFM
1.08W
9V
20 dBA@1m
960 RPM
42 CFM
0.83W
7V
19 dBA@1m
790 RPM
32 CFM
0.68W
5V
<18 dBA@1m
570 RPM
21 CFM
0.53W
@25 cfm (5.5V)
<18 dBA@1m
620 RPM
24 CFM
0.57W

At 12V, we'd characterize both fans as being smooth and very quiet but audible, with the nod going to the slower Nexus. The Scythe has a bit more growl that disappears below 7V. At 9V, a similar difference was heard but much reduced. Given the typical ambient noise for most homes (and certainly offices), many users will find either fan inaudible at this voltage. Both fans were just barely audible at 7V and inaudible from one meter at 5V.

Cooling Performance

Scythe Andy Samurai Master w/ stock or reference 120 fan
Fan Voltage
Temp
°C Rise
°C/W
12V
38°C
16
0.21
9V
42°C
20
0.26
7V
46°C
24
0.30
5V
51°C
29
0.37
Load Temp: CPUBurn for ~20 mins.
°C Rise: Temperature rise above ambient (22°C) at load.
°C/W MP / TDP: based on the amount of heat dissipated by the CPU (measured 78W); lower is better.

Scythe Andy vs. Scythe Ninja vs. Thermalright Ultra-120
Fan Voltage
Scythe Andy
Scythe Ninja
Ultra-120
°C Rise
°C/W
°C Rise
°C/W
°C Rise
°C/W
12V
16
0.21
14
0.18
15
0.19
9V
20
0.26
16
0.20
17
0.21
7V
24
0.30
17
0.21
21
0.27

Fan @ 12V: The stock fan was quiet at full speed, which is unusual. It was quieter than just about any other stock heatsink/fan we've tested, except for the Scythe Infinity, which came with the same model of fan. The noise consisted of a smooth midrange hum and slight low frequency growl that was easy to tune out. Compared to the Nexus, the stock fan sounded more tonal but produced less turbulence noise.

The cooling performance was excellent, very close to the Scythe Ninja and Thermalright Ultra-120, which are the top dogs in our entire database of tested heatsinks. Differences of 1~2°C are generally too close to the margin of error to call definitive, so you could say that the aforementioned models and the Andy have essentially the same cooling performance with this level of airflow.

Fan @ 9V: The stock fan actually became quiet enough to be considered an acoustic non-factor in most systems. It is a challenge to build a system that is quieter than the stock fan at this voltage — for many people, there may be no acoustic benefit to slowing the fan any further.

Performance remained very good, but the lead of the Ninja and Ultra 120 increased increased to 3-4C, which is significant. The tighter spacing of the ASM's fins was beginning to show their effect.

Fan @ 7V: At this level, the Nexus fan and the stock fan were both basically inaudible from one meter. There would be little point in reducing the fan speed any more. In a system with other sources of noise, the difference would not be heard. Only a slight low frequency hum let us know that the stock fan was spinning, and that was audible only when closely listened for.

The Andy's performance fell further from the Ninja and Ultra-120. We expect this is due to the higher impedance of the tighter spacing between fins, interleaved or not. For most systems, the performance is still good enough for safe temperatures.

Fan @ 5V: Both fans were inaudible from one meter at this level. The 29°C temperature rise is borderline peformance, however. The temperature inside a case could be easily 10°C higher than the 22°C measured on our open bench. This would mean a CPU temperature in excess of 62°C, which is still within safe limits, but getting close. There's no real acoustic advantage to running the fan this slow, so this data is not really that relevant.

ANDY VS. INFINITY VS. SI-128

It's an obvious comparison: The Infinity is Scythe's previous "interleaved" fin heatsink, while the SI-128 is the closest competition from Thermalright, except, of course, that it is a lot smaller and has 1/3 fewer heatpipes. (Note: The Infinity was retested on the new heatsink testing platform with the fan mounted on the wide side. The results here are slightly different than in the original Infinity review, which used a different CPU and motherboard.)

Scythe Andy vs. Scythe Infinity vs. Thermalright SI-128
Fan Voltage
Andy
Infinity
SI-128
°C Rise
°C/W
°C Rise
°C/W
°C Rise
°C/W
12V
16
0.21
16
0.21
21
0.27
9V
20
0.26
18
0.23
26
0.33
7V
24
0.30
20
0.26
29
0.37

The two Scythe heatsinks performed the same wth the fan at 12V. As the airflow was reduced, the Infinity took the lead pretty decisively. The Thermalright is clearly disadvantaged by its smaller size. It's in a different class altogether.



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