VGA Coolers: Thermalright V1 Ultra, Zalman 700 & 900, AC Silencer 5 v.3

Cooling
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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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