Arctic Cooling Alpine 7 Pro: The Alpine 7 Revisited

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TESTING


On the test bench...

Testing was done according to our unique heatsink testing methodology. The close integration between the fan and the heatsink made it impossible to use our usual reference fan, so the two were tested together as a single unit rather than our usual practice of considering the two separately. For the reason, we did not profile the fan separately. A quick summary of the components, tools, and procedures follows below.

Key Components in Heatsink Test Platform:

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-speed fan controller, 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 4.33, used to monitor the on-chip thermal sensor. This sensor is not calibrated, so results are not universally applicable, but they should be comparable with the other tests we've done on this test bed. The current test system was put into service in January 2007.
  • CPUBurn P6, used to stress the CPU heavily, generating more heat that most realistic loads. 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 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. 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 17 dBA and 21°C.

TEST RESULTS

Arctic Cooling Alpine 7 Pro with Stock Fan
Fan Voltage
Temp
°C Rise
°C/W
Fan Speed
Noise
12V
50°C
29°C
0.37
1,950 RPM
32 dBA@1m
9V
53°C
32°C
0.41
1,600 RPM
27 dBA@1m
7V
57°C
36°C
0.46
1,340 RPM
22 dBA@1m
5V
64°C
31°C
0.55
940 RPM
19 dBA@1m
Load Temp: CPUBurn for ~20 mins.
°C Rise: Temperature rise above ambient (21°C) at load.
°C/W: Temperature rise over ambient per Watt of CPU heat, based on the amount of heat dissipated by the CPU (measured 78W).
Noise: SPL measured in dBA@1m distance with high accuracy B & K SLM

Fair warning: This is a $15 heatsink. It's not meant to be a performance monster; it's meant to be quiet. By Arctic Cooling's own testing, it only manages to equal Intel's stock cooler in thermal performance. The difference? A drastic reduction in noise.

With that out of the way, we can move on to the results, which, at full speed, are just barely good enough to keep our 78W processor cool in a real system. Bear in mind that our heatsinks are tested in open air, which is at least 10°C cooler than the inside of a typical computer case. But, also bear in mind that 78W is on the toasty side these days — a midrange Core 2 Duo chip probably consumes about half this when driven at full load (most systems aren't).

12V: The noise at this level was, uhm, noisy. Not record-breaking, jet-engine noisy, but too noisy to meet our 30 dBA@1m threshold for "quiet" performance. The noise character was evenly split between turbulence noise and a soft whine. The whine was a fairly low tone, so it wasn't especially intrusive, but it was definitely enough to color the noise character of a system.

Cranking the fan down to 9V dropped the SPL below the 30 dBA@1m threshold, and the noise balance shifted towards turbulence noise. A small amount of whine was still apparent, and the fan remained audible. The drop in noise was greater than the drop in cooling performance, which dropped off by a marginal 3°C. For our 78W processor, this might be too much, but most processors should still be cooled acceptably at this level, especially in real world conditions where the load is less constant than our heavy CPUBurn test.

With a cool processor, the ~1,300 RPM mark at 7V is probably the ideal maximum adjustment point. Here, the tonal noise disappeared almost completely, leaving a soft white noise that blended easily into the background. It's quite likely that other system components will be louder at this level. With a low-to-mid processor and a motherboard with decent fan control, the fan need never spin much faster than this, suggesting that the Alpine 7 Pro could make good set-and-forget heatsink for a budget system.

At 5V (with the fan still spinning at a fairly quick 940 RPM), the noise was just barely distinguishable from the background noise. Enclosed inside a case with other noise sources, it would be completely silent, even in our quiet lab. Cooling at this level was unacceptable — for safety's sake we don't recommend running the heatsink fan this slowly. However, it is perfectly acceptable while the CPU is idling, and, in a system that is not heavily used, an advanced automatic fan speed controller (in a motherboard) might never push it above this level.

In most systems, the Alpine 7 Pro will not be used at a constant voltage level as it was tested here. Most users interested in the Alpine 7 Pro will probably want to use motherboard fan control to regulate the fan speed, ensuring that it only speeds up when it is needed. Whether or not the Alpine 7 Pro is quiet depends largely on how hot the processor is, although system airflow and usage pattern also play a role.

Given the price point and target market of the Alpine 7 Pro, we don't know how it stacks up against its competition. In performance, it is blown out of the water by almost every other heatsink we've tested on our current test bed — but most of these are priced around US$50 or higher and are designed for high performance. Even the low end heatsinks in our database start around ~US$30, so a fair comparison is difficult to make.

Ideally, it would be compared against Arctic Cooling's previous heatsinks (especially the Alpine 7 / 64), but these were tested on a previous iteration of our test bed, and they are no longer available for re-testing on the current system. Faced with this difficulty, we've elected not to compare the Alpine 7 Pro directly against any other heatsinks we've tested. Instead, we let it off with the following recommendation: If you're looking for a quiet $15 heatsink, the Alpine 7 Pro will probably work fine if your CPU is cool enough (say 65W TDP or lower, but ideally, under 45W) and your system cooling is decent.



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