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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°C, 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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