A small footprint silent PC that’s been running in our anechoic chamber is the subject of this article. DIYers could have fun with our design.
It’s been a while since we’ve featured any SPCR staff or lab systems. Here’s
one that works in our lab, in the anechoic chamber, specifically. Its main function
is to be the platform on which fans and hard drives are tested, particularly
for their acoustic characteristics. Since our chamber has an ambient level of
10~11 dBA, it is really important for all test gear in the room to make as little
noise as possible. Everything electronic in the chamber runs without a fan most
of the time (except for the power supply load tester, which whose fans are manually
shut off when sound measurements are recorded).
The PC in the chamber has to be…
1) Silent: This usually means no fans, no HDDs, and as little electronic
noise (high pitched whining or buzzing) as possible.
2) Easy access to headers & ports: Fan headers and SATA connectors
with a normal PC is can be reached only when the cover is removed.
3) Minimal footprint: The work bench top is about 5′ x 3.5′, and space
on it is often tight, so it needs to have as small a footprint as possible.
4) Energy efficient: It’s left idling or running for long periods.
High efficiency also minimizes the heat radiated into the small unventilated
Some years ago, we showed you a fanless PC for benchwork,
Silent PC with No Moving Parts. It was equipped with components that
had no moving parts at all, and zero electronic noise, thus utterly silent.
It doesn’t look like much, but it is utterly silent. There are no moving parts except for the floppy; even that’s silent once the Hitachi Feature Tool HDD utility is loaded.
But the footprint of this horizontally laid-out PC was pretty big, and it was
eventually retired. We needed a PC with a smaller footprint.
What took its place is a full ATX setup, configured vertically. The ASUS
P8Z77-V Pro motherboard was chosen for its outstanding FanXpert fan control/analysis
utility. The rest becomes obvious when you examine the photos.
Vertical Caseless Lab PC Components:
- ASUS 8Z77V-Pro – Intel
LGA1155 motherboard with excellent fan control system on mutiple heads
G540 2.50 GHz LGA 1155 Processor
2-core 65W TDP CPU – It runs really cool and has plenty of horsepower for
the system requirements. The built-in HD Graphics 2000 is perfectly adequate.
- Two 1GB sticks of DDR3-1333 ECC DRAM – Inherited from a HP
Microserver that got its RAM upgraded. Runs everything on our Windows
7 Ultimate 64bit OS perfectly.
- Intel X25-M 80GB SSD – Silent, fast and reliable.
SS-350TGM TFX 80PLUS GOLD
– This SFF PSU runs silently to ~150W. Its fan has never turned on in this
- Xigmatek Gaia CPU Cooler – It was on hand at the time, but any number
of other coolers would do the job fine, for example, the Silverstone
(The cooler fan was plugged in with FanXpert set to keep it off till the CPU
hit 60°C, but this often interfered with our fan testing, and the CPU
never got that hot anyway, so it was disconnected at some point. Removing
it would probably improve cooling but even with the fan mounted, the fins
barely get even warm to touch, so…)
AIDA64 gives you
On to the photos:
At its core are two pieces of scrap wood board, screwed together in an upside
down T-profile. The vertical board is just big enough for the ATX motherboard,
and the horizontal one is just big enough for a PSU on the other side, and to
keep the whole structure balanced. Felt pads on the bottom allow easy sliding
movement. Every port is easily accessible, and the fan headers that are a bit
more difficult to reach around the tower CPU cooler have 4-conductor extension
The CPU heatsink/fan does hang over the base quite a bit. The orientation of
the heatsink fins was meant to provide good passive convection airflow. Now
that it has been in use for a couple of years, it’s clear that the 65W TDP Celeron
G540 CPU runs cool enough that a much smaller heatsink can be used.
On this side, the 80+ Gold 350W
Seasonic TFX reviewed in 2012 is simply strapped on with elastic cord. The
PSU fan doesn’t turn on till ~150W load; in this system, the fan has never turned
on. An old Intel X25-M 80GB SSD is the sole storage device. It has plenty of
capacity for the programs and data in this system.
A port extension provides extra USB 2.0 ports on the top. A legacy four channel
voltage controller provides manual control for fans that balk (for whatever
reason) at the PWM control of the ASUS FanXpert utility that is our preferred
fan analysis/control utility.
So does this system work? Yes, very well, for its intended functions.
Is it quiet? Yes, it’s essentially silent. There might be a trace
of electronic whine from the PSU under certain conditions, but it is at too
low a level and too infrequent to be a problem. A CFL light in the room buzzes
a bit, and that could the the source of the whine, too. The CFL gets
turned off in favor of an old incandescent floor lamp when audio measurements
or recordings are done.
What could be improved? The cooler is actually bigger than it
needs to be. I would consider replacing it with a much smaller top-down style
cooler, something with widely spaced fins that can be mounted with the fins
aligned vertically for best convection air flow. This would reduce the footprint
to the size of the base wooden board. A PSU with modular cabling, perhaps one
of the SilverStone
units, would also be nice, to keep cable clutter to a minimum.
What about EMF shielding or the absence thereof? TBH, this hasn’t
been an issue with any of the open bench PCs that have run at SPCR for >15
years. There are no anomalies in other electronics or heath issues that can
be attributed to this electromagnetically unshielded PC. Oh, wait! Mobile phones
sometimes have poorer reception near these open bench PCs.
Would you recommend this type of system for SPCR readers? Generally,
no, simply because most users don’t need the instant wide open access to ports
that the system was designed for. And the lack of more graphics power means
most modern games are out of the question.
A handy Do-It-Yourselfer could shape a 5-sided perforated metal cover over
the whole shebang to make it safer and more attractive, and install a more powerful
CPU and a PCIe graphics card (perhaps one of the nVidia GTX 900 or 1000 series)
while keeping the footprint and overall size of the system the same as our rough
lab top system here. It would certainly run cool due to the wide open ventilation
and with the right cooling system on the graphics card, it could be pretty quiet
even during full-tilt gaming. (The ASUS
graphics cards, and MSI’s
models, for example, have both proven to be exceptionally quiet.) I’m planning
my next desktop system based on this design, using an ASUS Maximus VIII Gene
board, a Silverstone SFX-L PSU, and a steel perforated cover. Whether it features
a discrete graphics card or not is still up in the air. I’ll report back if
it gets done. 😉
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