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OVERCLOCKING
The extreme efficiency of the cooling system prompted us to see just how
much we could stress the system by overclocking it. Unfortunately, the motherboard
did not allow the PCI bus speed to be locked or overvolting above the stock
1.308V (undervolting is possible), so our overclocking attempt may have been
limited by these factors. In preparation for overclocking, memory timings were
loosened to 4-4-4-10 from 2-2-2-8 and the northbridge was overvolted to 1.50V
from 1.05V. Because the multiplier could not be adjusted upwards from 15x, all
overclocking was done by adjusting the FSB.
Our first attempt at overclocking the FSB to 167 MHz (2,505 MHz processor frequency)
was stable enough to run CPUBurn and 3DMark05, but it crashed five hours into
a session of Prime95. We then backed off in single MHz increments until all
our benchmarks would run properly. Strangely enough, the most unstable application
appeared to be 3DMark05; after its first successive run at 167 MHz, it crashed
repeatedly at every level above 163 MHz. This level proved to be stable after
48 hours of continuously running Prime95, so we feel confident that this was
the highest stable frequency. Multiplied by the 15x CPU multiplier, this translates
into 2,445 MHz as the highest stable processor frequency — a 22% overclock.
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Puget Custom Computer: Overclocking Test
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Activity State
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CPU Temperature
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AC Power Draw
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Idle
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31°C
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68W
|
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CPUBurn
|
43°C
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81W
|
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3DMark05
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41°C
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113W
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|
3DMark05 + large file
copy from CD to HDD
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41°C
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123W
|
Temperatures did not change significantly in the overclock. CPUBurn only increased
the peak temperature by a single degree and every other test we ran produced
results identical to those of the non-overclocked CPU.
The effect on AC power draw was similarly small, typically in the range of
2-3W. Running CPUBurn did increase this difference to 5W, but it's important
to keep in mind that CPUBurn is an exceptionally CPU-intensive program; most
real applications do not match this level of stress on the CPU.
PERFORMANCE BENCHMARKS
While the system was overclocked, we ran PCMark04 and 3DMark05 to obtain benchmark
scores. All possible tests were enabled, but all other settings were otherwise
left at their default values. The final scores were compared to other scores
in Futuremark's
benchmark database.
Our score ranked fourth among all Pentium M systems.
This test scores second in Futuremark's database for Pentium M systems
with a Radeon X800 XL, but there's only two other contenders.
We could probably have stolen first if we'd overclocked the VGA card too...
SOUND TESTING
In general use, the Puget system was inaudible except when specifically listening
for it. We had to put our ear within a foot of the case to clearly distinguish
the noise it makes from the ambient noise. The noise comes mainly from
the pump motor, and is characterized by a low frequency hum similar to hard
drive resonance or DC transformer hum. Puget did not disappoint: In most environments,
this system should be silent. The SPL measurement taken here is actually somewhat questionable; it is about the ambient noise level of the lab. It's possible (but unlikely) that the SPL is even lower than 18 dBA at 1m.
The one acoustic flaw in the system is the DVD burner. Puget selected the most
expensive DVD burner money can buy for the system, a SATA interface Plextor
drive, perhaps hoping that its high-end status would translate into a quieter
design. Unfortunately, the Plextor drive cannot overcome the inherently noisy
nature of high-speed optical drives; while the drive noise is reasonably smooth,
it is far from quiet at full speed.
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Puget Custom Computer: Noise Level
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Activity State
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SPL (dBA/1m)
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Idle
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18
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Hard Drive Seek
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18
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Full Speed CD Copy
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38
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CONCLUSIONS
When Puget first contacted Mike, they asked what
kind of system SPCR would like to review. Mike's reply was that he'd like to see a system
that SPCR audiences would like. A quiet, powerful and unique system would be great, he said. The
system that they sent meets all three of these criteria: It's unique, very
quiet, and very powerful.
This is probably not the kind of system that most people would
buy. The $3700 price tag is more than most people
will want to pay for a quiet system. The price includes more than $800
worth of custom parts and labor that are not available except by special request.
The custom-built water cooling system accounts for the lion's share of this
price, but there's also smaller details such as the soft rubber feet and the
custom-mounted hard drive enclosure that contribute to the price.
Taken on its own, the Puget system is a textbook example of overengineering.
Watercooling a Pentium M may indeed give the best CPU temperatures possible,
but it's far more than necessary. Soft rubber feet can be beneficial in a
system with high-vibration drives that sits on a hardwood floor, but they don't
really belong on a system of this weight. Building a fanless system that is
stable and doesn't overheat is an impressive feat, but it's possible
to build a system that is just as quiet using air cooling. Other examples of
somewhat redundant modifications include the use of a hard drive enclosure on a notebook
drive, and installing Acoustipack in a system that has next to no vibration.
As a demonstration of what Puget
can do, this custom system succeeds marvelously. Very few companies that sell whole systems
are willing to do the kind of modification that this Puget system required. A
self-contained, passively cooled water cooling system is not the kind of thing
you can request of just any system builder. With the proper selection of parts,
just one of Puget's modifications could make the difference
between an audible and an inaudible system.
Puget has
demonstrated that they can build a system that is not just quiet but silent
under most circumstances. No other system integrator that we know of can make this boast.
One reason that the Puget system is so quiet is that the basic components of
the system are quiet. The fanless power supply, notebook drive, and low-heat
Pentium M would all allow for a quiet system regardless of what other modifications
were made. Hopefully, this means that Puget is capable of building quiet systems
without taking the extreme approach that they used for our test machine.
Much thanks to Puget
Custom Computers for building us this customized review sample.
* * *
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