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TESTING
On the test bench...
Test Platform
- Intel
P4-2.8A The Thermal Design Power of this P4-2.8 (533
MHz bus) is 68.4 or 69.7W depending on the version. As the CPU is a demo model
without normal markings, it's not clear which version it is, so we'll round
the number off to ~69W. The Maximum Power, as calculated by
CPUHeat
& CPUMSR, is 79W.
- AOpen
AX4GE Max motherboard - Intel 845GE Chipset; built-in VGA. The on-die
CPU thermal diode monitoring system reads 2°C too high, so all readings are
compensated up by this amount.
- OCZ DDRAM PC-4000, 512 MB
- Seagate Barracuda IV 40G 1-platter drive (in Smart
Drive)
- Seasonic
Super Tornado 300 (Rev. A1)
- Arctic Silver
Ceramique Thermal Compound
- Nexus
Real Silent 92mm fan
- Two-level plywood platform with foam damping feet. Motherboard on
top; most other components below. Eases heatsink changes and setup.
Measurement & Analysis Tools
- CPUBurn
processor stress software
- SpeedFan
version 4.25 software to show CPU temperature
- A custom-built variable DC power supply that allows us to dial in exactly what voltage
is powering the fan
- B&K model 1613 sound level meter
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. The heatsinks were tested both with the stock
fan and our standard reference fan, a Nexus.
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. Every fan was tested at four voltages: 5V,
7V, 9V, and 12V, representing a full cross-section of the fan's airflow and
noise performance.
The ambient conditions during testing were 16 dBA and 23°C.
TEST RESULTS
| nMedia Icetank |
|
Fan Voltage
|
Load Temp
|
°C Rise
|
°C/W MP
|
°C/W TDP
|
Noise
|
| Stock Fan |
|
12V
|
40°C
|
17
|
0.22
|
0.25
|
35 dBA@1m
|
|
9V
|
43°C
|
20
|
0.25
|
0.29
|
29 dBA@1m
|
|
7V
|
45°C
|
22
|
0.28
|
0.32
|
24 dBA@1m
|
|
5V
|
50°C
|
27
|
0.34
|
0.39
|
20 dBA@1m
|
| Reference Fan (Nexus 92mm) |
|
12V
|
47°C
|
24
|
0.30
|
0.35
|
22 dBA@1m
|
|
9V
|
52°C
|
29
|
0.37
|
0.42
|
19 dBA@1m
|
|
7V
|
58°C
|
35
|
0.44
|
0.51
|
<18 dBA@1m
|
|
5V
|
71°C
|
48
|
0.61
|
0.70
|
<18 dBA@1m
|
|
Airflow: Measured in Cubic Feet per Minute mounted
on the HS
Load Temp: CPUBurn for ~20 mins.
°C Rise: Temperature rise above ambient at load.
°C/W MP / TDP: Temperature rise per Watt, based on CPU's Maximum
Power (79W) or Thermal Design Power (69W) rating (lower is better)
Noise: SPL measured in dBA/1m distance with high accuracy B &
K SLM
|
With the Stock Fan
@ 12V: At full speed, the stock fan generated a lot of airflow
and did an excellent job of cooling — better than any other 92mm heatsink
we've tested. The only tested heatsink to equal it is the Asetek Vapochill Micro,
at a whopping 45 dBA@1m. The Icetank fan was significantly quieter than that, but still too loud at ~35
dBA@1m. The noise was split evenly between turbulence noise and a mechanical
hum.
@ 9V: Cooling efficiency dropped only a little when we decreased
the fan speed to 9V, and noise dropped to just below the 30 dBA@1m boundary
that we consider quiet. The most prominent difference was a large drop in
turbulence noise, which was now only a minor factor. Unfortunately, the drop in broadband noise uncovered
a slight rattle that could not be heard before.
@ 7V: This level offered the best compromise between noise
and cooling, with performance only 5°C off the maximum speed, and noise
at a comfortable 24 dBA@1m. Unfortunately, even though the noise level was fairly
low, the fan developed a repetitive chuffing sound that replaced the hum
from before. The chuffing was intrusive, and could not be changed without
swapping the fan. The rattle that was audible at 9V sounded worse at 7V, as
it was no longer partially obscured by other noise. In combination with the
chuffing, the fan sounded much worse that it measured.
@ 5V: Even at 5V, the Icetank was still going strong. The
27°C rise from ambient was perfectly acceptable for our processor; it
could probably run safely even in the warmer confines of a computer case.
That being said, the temperature would probably close to the maximum —
a hotter chip might not be cooled adequately. Unfortunately, noise did not drop much below the 7V level. The noise could
still be heard clearly above the ambient noise, and the clicking and chuffing
made it easy to identify. A new fan is needed to make the noise level acceptable
in the quietest of systems.
With the Nexus 92mm Fan
@ 12V: Conveniently, we happened to have a 92mm Nexus fan (our
reference) that allowed the noise level to be dropped further. At full speed,
it measured roughly the same as the stock fan at 5V, and sounded much nicer
to boot. Performance with the Nexus was still quite good — comparable
to the stock fan at ~6V.
@ 9V: At 9V, the Nexus was close to the ambient noise level,
and cooled only little worse than the stock fan at 5V — i.e. good enough
for our test processor. Most AMD-based systems run cooler than our P4 Northwood
2.8 GHz, so a large portion of PC users could achieve
near silence with this heatsink and the Nexus or a similarly quiet fan.
@ 7V & 5V: Below 7V, the Nexus was more or less inaudible
from one meter. Cooling was not quite good enough for our test processor to
survive in an actual system unless airflow was carefully planned, but a cooler
processor could easily be cooled at this level. At 5V, the processor temperature
skyrocketed; this was clearly too little airflow. However, the audible difference
between 7V and 5V was so small that there would be little point to reduce
the fan below 7V.
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