[CentOS] Off-Topic: Low Power Hardware

Mon Jan 14 17:47:01 UTC 2013
SilverTip257 <silvertip257 at gmail.com>

On Mon, Jan 14, 2013 at 11:20 AM, Matt Garman <matthew.garman at gmail.com>wrote:

> On Fri, Jan 11, 2013 at 8:55 AM, SilverTip257 <silvertip257 at gmail.com>
> wrote:
> > I'm in search of some hardware that consumes a low amount of power for
> use
> > as a test-bed for Linux, various coding projects, and LAN services.
> >
> > 1) Low power consumption (10-15W ... maybe 30W at most)
> > 2) Must run Linux without too much fuss (CentOS or otherwise)
> > 3) Must have two NICs (fast ethernet or better)
> > 4) Memory - 1GB or better
> > 5) Can be configurable either via serial or VGA.
> > 6) Accepts a normal hard drive, not CF -- drive capacity is my concern.
> > 7) spare PCI slot is a _plus_ (extra NICs or whatever else)
> > 8) I'd like to keep the physical footprint to a minimum (size of a 1U
> > switch or so?)
> The lowest-power x86 device I've used is an Alix 2d2 from PCEngines.
> Power consumption was about five watts, regardless of load.  This has
> three 100 mbps NICs, a 32-bit x86 AMD Geode CPU, and 256 MB RAM
> soldered to the board.  Has a built-in Compact Flash slot to use as a
> "hard drive".  I ran OpenBSD on mine for years as a
> firewall/gateway/router for a home LAN (don't see why it wouldn't run
> CentOS).  (I'm actually selling mine, email off list if interested.)

The Geode CPUs do not support PAE [0].  While CentOS 5.x would work, 6.x
requires a kernel recompile (not complaining, but noting).

[0] http://joseph.freivald.com/linux/2010/04/22/alix-centos-image/

> I upgraded my firewall device to an Atom-based D2500CCE.  IIRC, I
> installed 2x2GB of RAM, booting from a cheap SSD, powered by a
> PicoPSU, and running PFSense.  I think this configuration pulls
> roughly 16 watts at idle, maybe a couple more watts when fully loaded.
>  This board has dual Intel gigabit ethernet ports.
> For my home theater PC, I'm running an ASRock H67M-ITX and Core
> i3-2100 CPU, with 2x4GB of RAM and SSD.  I have it inside a Habey
> EMC-800B case, using the included power supply.  Idle power
> consumption is about 22 watts.  It's been a while since I measured
> power consumption at load, but I'd guess 50--60 watts (it's idle 99%
> of the time though).  Note that even when "idle", MythTV seems to use
> a little CPU, so if I kill mythfrontend, my idle power consumption
> drops another watt or two.
> Only one NIC on the Asrock board, but it has a PCIe expansion slot so
> you could easily add another.  I'd expect an add-on NIC to add around
> one to five watts of power consumption.
> My personal workstation uses an Intel DH67GD micro-ATX motherboard,
> i5-2500k CPU, 4x4GB RAM, SSD, and traditional ATX power supply
> (Seasonic SS-300ET).  It pulls about 30 watts when idle.  Only one NIC
> on that motherboard.
> For all the above, I'm talking AC (i.e. at the wall) power
> consumption, in the USA (so 115 Volts), measured with a Kill-A-Watt
> (not high-precision, but should be reasonable within a watt or two).
> What follows is stuff with which I have no personal experience, but
> have read about:
> The Intel S1200KP mini-itx motherboard.  It has built-in dual gigabit
> NICs, socket 1155, so you can use anything from a Celeron up to a
> Xeon, depending on how much you want to spend and what your
> upper-bound computational needs are.  I was considering that for my
> firewall/router replacement.  With a PicoPSU I would suspect that one
> could get 20 watts or lower idle power consumption.
> With an Intel DQ77KB motherboard, and Pentium G2120, SilentPCReview
> built a system that pulls 16.5 Watts[1].  (The article is a case
> review, but power consumption information is included.)  That DQ77KB
> board also has dual gigabit NICs.
> You might also be interested in Intel's "NUC - Next Unit of
> Computing"[2].  About 10 watts power consumption for dramatically
> under-clocked i3 CPU.
> In general, with modern Sandy/Ivy Bridge CPUs, it's almost trivial to
> build a high-performing system that has 30 watt or less idle power
> consumption.  If you cherry-pick components, it's not terribly hard to
> get a system with 20 watt idle power draw.  The modern Intel CPUs all
> have roughly the same idle power usage (at least the consumer line,
> not sure about Xeons).  That goes for the more expensive low-power
> variants as well.  The difference of the low-power variants is their
> upper-bound power consumption is lower than their peers.  But you can
> often fake that by deliberately limiting the max frequency in the
> BIOS.  Of course, with these "real" CPUs (compared to e.g. Atom),
> power consumption will be much higher when loaded.  But from what I've
> read, the "real" CPUs are actually better in the long run, because
> their computation efficiency is so much higher.  With something like
> Atom, you get more deterministic power draw, but a severely
> compromised upper-bound on computational power.  In your requirements,
> you mentioned "various coding projects".  If you are working in a
> compiled language (e.g. C, C++, Java), for substantially large
> projects, your compile times will be painful on Atom, but pleasantly
> fast on a Sandy/Ivy Bridge CPU.

I'll have to keep the 'real' cpu point in mind because after all this box
will be idle much of the time.

> [1] http://www.silentpcreview.com/Akasa_Euler_Fanless_Thin_ITX_Case
> [2] http://www.silentpcreview.com/Intel_NUC_DC3217BY
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//  SilverTip257  //