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TEST RESULTS
Stock Fan Testing
The stock fan is a double ball bearing PWM model with translucent blades. One
of the struts points directly upward contrary to the other three — this may
help break up any tonality generated by the fan.
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Stock Fan Specifications
|
| Manufacturer |
Zalman |
Power Rating |
4.8 W |
| Model Number |
ZF1125BTH |
Airflow Rating |
? |
| Bearing Type |
Double ball bearing |
RPM Rating |
1000~2150 RPM +/- 10% |
| Hub Size |
42.7 mm |
Noise Rating |
20.0~39.0 dBA |
| Frame Size |
120 x 120 x 25 mm |
Header Type |
4-pin PWM |
| Weight |
130 grams |
Starting Voltage |
5~6V (varies) |
| The data in the blue cells is provided by the manufacturer;
we measured the data cited in the green cells |
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TEST MEASUREMENTS
|
|
Voltage
|
Noise Level
|
Speed
|
|
12V
|
37 dBA
|
2180 RPM
|
|
9V
|
31 dBA
|
1730 RPM
|
|
8V
|
27 dBA
|
1560 RPM
|
|
7.5V
|
15 dBA
|
1130 RPM
|
|
7V
|
12 dBA
|
680 RPM
|
|
6V
|
11~12 dBA
|
550 RPM
|
|
5V
|
11 dBA
|
410 RPM
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Regular readers will notice that the measurement points are not at the usual 12, 9, 7 and 5 volts. This PWM fan, like many others, does not have as linear a relationship with voltage as normal DC fans. Between 9V and 7V, there
is a huge drop in fan speed, which required finer voltage gradations to be tested.
Fan @ 12V: Extremely loud, turbulent, and whiny.
Fan @ 9V: Buzzy with a low-pitched hum. Still too loud at 31 dBA.
Fan @ 7.5V: Smooth with only a touch of hum. Fairly quiet at 15 dBA.
Fan @ 7V: Still smooth and almost inaudible from one meter's distance.
Very little bearing noise.
Fan @ 5V: Inaudible except at close proximity.
The stock fan was too loud between 12V and 8V, but between 8V and 7V, there
is a huge drop in fan speed resulting in some serious acoustic improvement.
The hum breaks down and the motor emits only a very slight rattle. At lower
speeds, it is surprisingly pleasant and smooth. On previous Zalman heatsinks,
the fan's impeller was always mounted on thin pieces of metal so it could be
integrated into its "flower" design. A fan with a proper frame doesn't
vibrate nearly as much and it makes worlds of difference.
|
Fan Controller Modes
|
|
Mode
|
Est. Equivalent Voltage
|
RPM
|
|
Red
|
12V
|
2180
|
|
Purple
|
11V
|
2000
|
|
Blue
|
7.8V
|
1450
|
|
Green (Manual)
|
7.3V to 12V
|
1010~2190
|
The included fan controller has three different set modes that run the fan
at 2180, 2000 and 1450 RPM. Manual mode allows it to spin at an approximate
minimum speed of 1000 RPM which is a fairly quiet level.
(Editor's Note: This fan is highly significant in that it is the very first from Zalman not to have the buzzy ball-bearing sound so characteristic of all previous Zalman fans. For a brand which has long emphasized low noise as a key feature, Zalman fans have been notoriously bad sounding. This new fan finally breaks tradition. It's almost worthy of a halleluja!)
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