Arctic Cooling Alpine 7 Pro: The Alpine 7 Revisited

Arctic Cooling has updated their quiet, budget socket 775 cooler with a new “Pro” version that simplifies installation by using Intel’s stock pushpins. The heatsink block has also been changed to accommodate the new mounting hardware. Is that all that has changed or has Arctic Cooling messed too much with a good thing?

January 30, 2008 by Devon
Cooke

The Alpine 7 Pro is the latest in a long line of budget heatsinks from Arctic
Cooling. Arctic Cooling built their reputation on these heatsinks, and they
remain one of the only manufacturers to bother with the low-end market. With average processor thermals dropping significantly over the last couple of years and improvements in the stock heatsinks from Intel and AMD, there’s little reason to upgrade for cooling performance alone. That leaves
noise as the main reason to upgrade — and that has improved too. (Editor’s Note: I beg to differ on this point — IMO, the sound quality of the stock fans on Intel heatsink remains among the nastiest at any speed.)

That said, one of the reasons for Arctic Cooling’s longevity is their reputation
for low noise. Although they’ve had a few duds along the way, they’ve always
paid attention to noise in their designs, and their frameless, soft-mounted
fans are unique in the industry.

The Alpine 7 Pro is a refinement of the
Alpine 7 / 64 design that Arctic Cooling has sold for the last year and
a half. The main difference seems to be the use of Intel’s pushpin mounting
system rather than a backplate + bracket system, but the heatsink itself has
also been changed to make room for the new hardware.

Minimal padding and clear plastic packaging is retail friendly, but not so good for protection or the environment.

PHYSICAL DETAILS

The heatsink itself is about as simple as they come: An octagonal
block of extruded aluminum topped by a fan. The fan is the most complex (and
probably the most expensive) part of the package. It’s not just a stock OEM
fan pulled off a shelf somewhere either; Arctic Cooling has adapted one of their
soft-mounted, frameless fans by adding simple plastic clips that hold it securely
against the heatsink fins.

A simple extruded aluminum fin based topped by a frameless 92mm fan.

The fin block is slightly smaller than the original Alpine 7 because of the
need to make space on the corners for the four pushpins. Thus, the block has
been trimmed down to size and the overhanging fins that prevented pushpins in
the original have been removed. A few fins have been added on either side so
that the fan blades no longer hang over the sides, but this doesn’t fully compensate
for the surface area lost elsewhere.

The fins alternate between two slightly different lengths so that the fan’s
frame only makes contact with about half of the fins. This is probably to allow better airflow in between the fins. At the interface closest to the fan blades, the apparent fin spacing is double the width of the actual fin spacing further below, which might mean less impedance and less air turbulence (due to back pressure). We’ve seen alternating fins on other heatsinks, such as the Scythe Infinity and some older heatsinks, too, so the feature must be relatively effective.

Fins alternate between two different lengths.

The mounting system requires no assembly, but it can be disassembled for repairs
or by the curious. It consists of two steel bars that screw into the bottom
of the fin block. Each bar holds two of Intel’s plastic pushpins. Installing
the heatsink in a system is tool-free, and fairly easy to do. (Unlike many of the massive heatsinks we’ve tested, this heatsink stays inside the boundary of the four pins, so that that access to the pins from the top is unrestricted. This is critical for ease of use with the Intel push pins.) First time users may struggle a bit
with knowing which way to keep the pins twisted (Intel’s arrow markings can
be a bit counterintuitive), but this is an issue with Intel’s design, not Arctic
Cooling’s.

Standard Intel pushpins.

The base of the heatsink comes with a thick layer of thermal compound pre-applied.
Arctic Cooling boasts of using their own high performance MX-2 thermal compound,
but so long as there is something between the heatsink and the CPU, the
exact thermal compound used is more or less irrelevant. For testing purposes,
we cleaned off the MX-2 compound and replaced it with Arctic Silver Lumière
as per our standard testing methodology.

The base is not especially smooth or polished; there are machining marks on
the bottom of our sample that run with the grain of the aluminum in the base.
As with the choice of thermal compound, the actual difference in
thermal performance is pretty minimal.

A large square of pre-applied MX-2 thermal compound.

FAN

The fan is the most unusual part of the Alpine 7 Pro. It’s a frameless 92mm
model adapted from Arctic
Cooling’s Arctic Fan 9 PWM. The current rating is slightly higher at 0.15A
vs. 0.13A, and the frame is adapted to fit on the fin block, but the fans are
otherwise pretty similar. We’ve examined a
120mm version of the same fan and been somewhat unimpressed by the
real-use effectiveness of all the low-noise design features. However, we thought
better of the fan on the original
Alpine 7.

For those who haven’t seen them before, Arctic Cooling’s fan have two features
designed to reduce noise: A "frameless" design, and a mounting system
that incorporates four soft rubber grommets to prevent vibration from causing
resonance. It’s a good system in theory, but in practice the whine of the motor
is still the main source of noise at high speeds. At low speeds, turbulence
and resonance are greatly reduced, so the anti-vibration measures tend to be unnecessary.

Nonetheless, the fans on Arctic Cooling coolers
have been some of the quietest stock fans around, especially at low speeds. We expect the same excellent performance out of the Alpine 7
Pro.

The fan is mounted on a heatsink-specific frame.

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:

• Intel Pentium D 950
  Presler core, rated at 130W TDP. Under our stress load, we measured 78W, which includes efficiency losses
  in the VRMs.
• ASUS P5LD2-VM
  motherboard. A basic microATX board with integrated graphics and plenty
  of room around the CPU socket.
• Hitachi
  Deskstar 7K80 80GB SATA hard drive.
• 1 GB stick of Corsair XMS2
  DDR2 memory.
• FSP
  Zen 300W fanless power supply.
• Arctic Silver
  Lumière: Special fast-curing thermal interface material,
  designed specifically for test labs.

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

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.

NOISE RECORDINGS IN MP3 FORMAT

• Arctic Cooling Alpine 7 Pro: 5V-7V-9V-12V, 5s leading ambient:
  One Meter (Note:
  The 30cm recording is unnecessary; the noise is perfectly audible at 1m.)
• Reference 92mm fan (not tested): 5V-7V-9V-12V, 5s Ambient between
  levels: One Meter,
  One Foot

Comparatives:

• Scythe Ninja Mini: 5V-7V-9V-12V, 5s Ambient between levels:
  One Meter,
  One Foot
• Zalman CNPS8700 LED: 5V-7V-9V-12V, 5s Ambient between levels:
  One Meter
• Scythe Mine w/ stock fan: 5V-7V-9V-12V, 5s Ambient between levels:
  One Meter, One
  Foot

FINAL CONCLUSIONS

The Alpine 7 Pro’s mediocre thermal performance is difficult to ignore —
but so is its ~$16 price. The only other heatsinks at this price level are
its predecessors from Arctic Cooling, and our verdict is much the same: It’s
a bargain for a low-to-midrange system.

What it lacks in performance it makes up in low noise. We were pleased to note
that this sample sounded smoother than previous Arctic Cooling fans we’ve heard,
and it certainly had no difficulty disappearing under the ambient noise when
turned all the way down.

As an upgrade from the Alpine 7, the pushpin mounting system is an
improvement, but little else has changed. Because our test bed has changed since
the original was tested, a direct comparison for performance is not possible.
In theory, the smaller surface area of the fins should actually degrade
performance a bit.

Ultimately, the utility of the Alpine 7 Pro comes down to the system it is
used in. With a cool processor it has great potential, but that still leaves
the question: "How cool?" That is not a simple question — far
too complex to be addressed here. Luckily, its price comes in handy — US$16
is not too much to put down for a little guess-and-test.

Much thanks to Arctic
Cooling for the Alpine 7 Pro sample.

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