Scythe Zipang 14cm fan "blow-down" CPU cooler

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:

  • Intel Pentium D 950 Presler core. TDP of 130W; under our test load, it measures 78W including efficiency losses in the VRMs.
  • ASUS P5LD2-VM motherboard. A basic microATX board with integrated graphics and plenty of room around the CPU socket.
  • Samsung MP0402H 40GB 2.5" notebook drive
  • 1 GB stick of Corsair XMS2 DDR2 memory.
  • FSP Zen 300W fanless power supply.
  • 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)

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 4.32, used to monitor the on-chip thermal sensor. This sensor is not calibrated, so results are not universally applicable.
  • 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'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 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 various voltages to represent a good cross-section of its airflow and noise performance.

The ambient conditions during testing were 15 dBA and 21°C.

TEST RESULTS

Fan Measurements

Stock Sycthe 140x25mm fan - We did a basic review of the stock fan's properties.


Stock fan.


Model Number DFS132512L Power Rating 0.12A
Bearing Type Sleeve Airflow Rating 51.82 CFM
Hub Size 1.73" RPM Rating 1000 rpm (±10%)
Frame Size 139 x 139 x 25 mm Noise Rating 21.00 dBA
Weight 160g Header Type 3-pin

Scythe DFS132512L Fan
Voltage
Noise
RPM
12V
23 dBA@1m
970 RPM
9V
18 dBA@1m
770 RPM
7V
16 dBA@1m
640 RPM
5V
<15 dBA@1m
470 RPM

The fan generated 23 dBA@1m at full speed, which is very low for a stock fan. At lower voltages it seemed so quiet that a special effort was made to measure and record the noise when the ambient was at its lowest in the lab — slightly less than 15 dBA at five o'clock one quiet morning. In many systems, this fan would be the quietest component even at full speed. It spins at approximately 1000 RPM at 12V down to about 500 RPM at 5V. The audio recording was scrapped for the noise at 5V; it was too close to the ambient, and extremely difficult to distinguish when the fan is turned on. So this fan recording starts at 7V. This fan is one of the quietest, nicest-sounding, stock fan SPCR has encountered in over six years of testing CPU coolers.

We were unable to determine the fan's starting voltage. When we started the test from 12V and decreased the voltage incrementally (turning the power source off and on at each interval), we found it could start up at 5V. When we started from a low voltage, and worked our way up, it would not start up reliably until 8V. After testing it on our heatsink testbed motherboard, we found that it will start up at 7V as long as the fan speed is never decreased to the point where the fan stops spinning. If this happens, up to 8V is required to get it going again. Both temperature and sample variance may come into play here.

Nexus 120x25mm reference fan refresh - We also took advantage of the very low ambient at this time to run tests on a newer sample of the Nexus 120 fan that we use as our reference. This is a version with open corner flanges, which makes it more versatile and useful for heatsinks. As expected, lower SPL numbers were obtained, due mostly to the lower ambient. There is a small possibility that this newer fan is a touch quieter due to wear and tear on the older one, and sample variance. The main thing is that the lower ambient gave us more resolution that just "<19 dBA" for <9V readings.

New Nexus 120 fan measurements
Voltage
Noise
RPM
12V
21 dBA@1m
1100 RPM
9V
17 dBA@1m
890RPM
7V
15 dBA@1m
720 RPM
5V
<15 dBA@1m
530 RPM


Cooling Results

Scythe Zipang
Fan Voltage
SPL @1m
Temp
°C Rise
°C/W
12V
23 dBA
40°C
18
0.24
9V
18 dBA
42°C
20
0.27
7V
16 dBA
47°C
25
0.33
5V
<15 dBA
58°C
36
0.47
Load Temp: CPUBurn for ~10 mins.
°C Rise: Temperature rise above ambient (22°C) at load.
°C/W: based on the amount of heat dissipated by the CPU (measured 78W); lower is better.

Fan @ 12V: The fan sounded smooth and very quiet. There was some slight chuffing evident close up, and a trace of tonality centered mostly around 900 Hz. Thermal rise was 18°C, excellent for a top-down cooler.

Fan @ 9V: The noise dropped substantially. From very close, there was some low-pitched buzzing and clicking. Overall, it was almost inaudible in our lab. The CPU temperature rose by just 2°C.

Fan @ 7V: It sounded very smooth, with only very minute clicking. At this point we could not hear the fan over the ambient noise, except from within about a foot distance. The 16 dBA@1m SPL could not have been measured in the lab except at ultra-quiet times... like 5AM. Performance dropped by a further 5¬įC, and the °C/W ratio rose just above the 0.3 mark that's our rough safe limit for cooling. In a real system inside a real case with a similar CPU under heavy long term load, this is probably as low a fan speed as you'd want to use.

Fan @ 5V: The fan sounded the same as at 7V — inaudible. There's no reason to drop the fan speed this low. Performance really suffered with an almost 10°C jump compared to 7V. The tight fin spacing and minimal airflow don't make a good combination.



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