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TEST RESULTS
Ambient conditions during testing were 19 dBA and 22~23°C. Tests were run
with the system fan at 12V, 9V, and then 7V. An additional test was run with
both the system fan and the VGA fan at a full 12V as an estimate of the best
possible cooling, regardless of noise.
Thermal testing consisted of running CPUBurn and the artifact scanner
built into ATI Tool simultaneously to generate as much heat as possible.
An initial test was run with the system fan running at 12 volts, and then the
fan was progressively slowed down to make the thermal environment more difficult.
As a general rule, the fan on the VGA cooler was kept at a quiet 5 volts, with
the single exception of the NV Silencer, which was powered by the fan header
on the test card. Based on the additional noise in the system, we would estimate
that the fan received approximately 10V from the header. The noise level did
not change appreciably during testing, so we can assume that the fan did not
change significantly in speed.
Once the temperature on the card had stabilized, the stress software was left
running for at least another 20 minutes while we watched the screen carefully
for visual artifacts that might indicate overheating. The last test, with the
system fan running at 7 volts, was left running for more than an hour. Even
during our most strenuous test, none of the coolers ever allowed our test card
to get hot enough that there were visual artifacts on the screen.
TEST 1: System Fan @ 12V, VGA Fan @ 12V
|
VGA Cooler Test Results: System Fan @ 12V, VGA Fan
@ 12V
|
|
Cooler
|
GPU Temperature
|
VGA Ambient
|
AC Power Consumption
|
CPU Temperature
|
System Noise
|
|
Arctic Cooling
NV Silencer 5*
|
68°C
|
61°C
|
221W
|
63°C
|
28 dBA@1m
|
|
Thermalright V1 Ultra
|
61°C
|
53°C
|
218W
|
60°C
|
34 dBA@1m
|
|
Zalman VF700CU LED
|
72°C
|
52°C
|
221W
|
63°C
|
32 dBA@1m
|
|
Zalman VF900CU
|
63°C
|
49°C
|
217W
|
62°C
|
30 dBA@1m
|
| *Exact fan voltage was supplied by the header on the VGA
card, and is therefore unknown. Based on the amount of noise it adds to
the system, we estimate that it received ~10V. |
At full blast, all of the coolers were more than capable of cooling our test
card. The Thermalright V1 Ultra and the VF900CU were more or less tied for the
best cooler, with the Thermalright delivering a slightly better core temperature
and the Zalman giving a better "ambient" temperature. The location
of the ambient sensor is unknown, so the result probably has more to do with
the location of the airflow than any absolute difference in cooling ability.
As a side note, the top mounted fan of the V1 Ultra provided a little bit of
extra cooling for the CPU.
On the other hand, the NV Silencer, which provides no airflow
that isn't around the GPU, produced a much higher ambient temperature than any
other heatsink. It seems that the secondary electronics (RAM, VRMs, etc.) are
better cooled with the unducted coolers.
All of the coolers were too loud to consider in a quiet system, although the
NV Silencer might be on the borderline. In all cases, the primary source of
noise was the VGA fan, not the rest of the system.
TEST 2: System Fan @ 12V, VGA Fan @ 5V
|
VGA Cooler Test Results: System Fan @ 12V, VGA Fan
@ 5V
|
|
Cooler
|
GPU Temperature
|
VGA Ambient
|
AC Power Consumption
|
CPU Temperature
|
System Noise
|
|
Arctic Cooling
NV Silencer 5*
|
68°C
|
61°C
|
221W
|
63°C
|
28 dBA@1m
|
|
Thermalright V1 Ultra
|
75°C
|
68°C
|
220W
|
60°C
|
26 dBA@1m
|
|
Zalman VF700CU LED
|
74°C
|
56°C
|
218W
|
61°C
|
26 dBA@1m
|
|
Zalman VF900CU
|
63°C
|
52°C
|
218W
|
60°C
|
27 dBA@1m
|
| *Exact fan voltage was supplied by the header on the VGA
card, and is therefore unknown. Based on the amount of noise it adds to
the system, we estimate that it received ~10V. |
What a different view from the quiet end of the spectrum! This time, the V1
Ultra was the worst performer and the VF900... hadn't changed. Sure, the ambient
temperature bumped up a few degrees, but the actual core temperature didn't
change. Shocked, we filed the result away for closer examination later.
The VF700 also did quite well with the fan turned down. GPU temperature crept
up by just two degrees, putting it at roughly the same level as the V1 Ultra
— at least where core temperature is concerned.
This time around, the mysterious "ambient" sensor was worth paying
attention to. While the two Zalman coolers kept the increase in "ambient"
to a respectable 3~4°C, the V1 Ultra skyrocketed by 15°C! Wherever the
sensor is, it is quite clear that the Zalman coolers do a better job of cooling
it with low airflow than the V1 Ultra.
The results for the NV Silencer didn't change — hardly a surprise because
we had no way of controlling the fan speed on the cooler, so the test that we
ran was identical. The results are included for comparison only.
The all of the VGA fans at 5V, the primary source of noise was no longer the
VGA fans but the system fan. Turning down the case fan was the logical next
step towards silencing the test system.
TEST 3: System Fan @ 9V, VGA Fan @ 5V
|
VGA Cooler Test Results: System Fan @ 9V, VGA Fan
@ 5V
|
|
Cooler
|
GPU Temperature
|
VGA Ambient
|
AC Power Consumption
|
CPU Temperature
|
System Noise
|
|
Arctic Cooling
NV Silencer 5*
|
67°C
|
61°C
|
221W
|
65°C
|
27 dBA@1m
|
|
Thermalright V1 Ultra
|
75°C
|
68°C
|
221W
|
63°C
|
24 dBA@1m
|
|
Zalman VF700CU LED
|
78°C
|
61°C
|
219W
|
65°C
|
24 dBA@1m
|
|
Zalman VF900CU
|
65°C
|
55°C
|
218W
|
63°C
|
24 dBA@1m
|
| *Exact fan voltage was supplied by the header on the VGA
card, and is therefore unknown. Based on the amount of noise it adds to
the system, we estimate that it received ~10V. |
The NV Silencer and the V1 Ultra were more or less unaffected by the change
in system airflow. With either cooler, the temperatures on the video card remained
constant, although the CPU temperature crept further towards throttling.
The VF900 was only slightly more affected; it allowed the GPU core to creep
up by a couple of degrees. Only the VF700 was affected seriously by the reduction
in system airflow, once again dropping a little behind the V1 Ultra.
By this time, the NV Silencer was looking pretty good. Only the VF900 managed
to beat it in in terms of performance. But, (and it's a big but) it was also
still the main source of noise in the system at this point, since its fan was
still running at close to full tilt. From a noise-for-performance perspective,
it was still less than satisfactory.
TEST 4:System Fan @ 7V, VGA Fan @ 5V
|
VGA Cooler Test Results: System Fan @ 7V, VGA Fan
@ 5V
|
|
Cooler
|
GPU Temperature
|
VGA Ambient
|
AC Power Consumption
|
CPU Temperature
|
System Noise
|
|
Arctic Cooling
NV Silencer 5*
|
68°C
|
62°C
|
222W
|
68°C
|
27 dBA@1m
|
|
Thermalright V1 Ultra
|
78°C
|
71°C
|
223W
|
66°C
|
23 dBA@1m
|
|
Zalman VF700CU LED
|
81°C
|
64°C
|
221W
|
65°C
|
23 dBA@1m
|
|
Zalman VF900CU
|
67°C
|
58°C
|
220W
|
67°C
|
23 dBA@1m
|
| *Exact fan voltage was supplied by the header on the VGA
card, and is therefore unknown. Based on the amount of noise it adds to
the system, we estimate that it received ~10V. |
Reducing the system fan to 7V was the last step in our test. Reducing it any
more would have been pointless from an acoustic point of view, since the system
noise did not really change below this level. The residual noise level of 23
dBA@1m was a combination of all of the noise sources in the system, with none
distinguishing themselves clearly as the primary noise source. Further noise
reduction at this point would have needed to take a more radical form that just
reducing fan speeds.
The final test revealed little new information except to confirm what we had
already learned: The VF900 was clearly the best low airflow cooler in our test. The maximum GPU temperature of 67°C was at least 10°C better
than both the V1 Ultra and the VF700. It would undoubtedly have had a similar
advantage over the NV Silencer if we had been able to reduce the latter's fan speed.
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