[svlug] Sheevaplug ?

Rick Moen rick at linuxmafia.com
Wed Oct 21 16:43:58 PDT 2009

Quoting Luke S Crawford (lsc at prgmr.com):

> Note, my test was done twice, once with the desktop dual-core atom board,
> and once with the SuperMicro dual-core atom board, with similar results.

FWIW, here's something I wrote up for members of my family (where I get
ragged on for running 24x7 server "uncle-enzo.linuxmafia.com" aka enzo
on the home ADSL, but nobody has much in the way of hard figures, and
where I can't help suspecting the ragging-on-Rick has more to do with
their justifying their own avoidable power wasteage than anything else).
I do (as of recently) have a Kill-A-Watt, and it's perhaps the only
reasonable way to get comparables that matter.

I.e., I imagine setting up candidates with loading from Cerberus Test
Control System (http://sourceforge.net/projects/va-ctcs/), the burn-in
suite we developed and used at VA Linux Systems -- and measuring with ye
olde Kill-A-Watt.

I make no apologies for handwavium in the below-cited mail.  ;->
Nailing down figures requires using said Kill-A-Watt.

Good point about differences among PSUs, by the way.  Forgot that.
(I love VPSes, but we're paying for the ADSL anyway, so the relevant
_cost_ comparison is PG&E hit for the home box, vs. fees for the VPS --
or colo.  Using the ADSL wins on cost, by that metric.)

 To: my family members
 Subject: Power consumption - CPUs, HDs

There's intermittant discussion on LUG mailing lists about power
consumption.  Nothing all that useful -- but it motivated me to look up
some figures.

Current enzo has:

1 x PIII 600 MHz CPU, mfr.-claimed draw 34.5 Watts
3 x 3.5" U320 SCSI drives,
     IBM      IC35L073UWDY10-0 S27Q, 73408 MB, 10k RPM: specs say it
              needs +5V and +12V feeds _capable_ of 14.94 Watt total,
              and the power-efficiency specs suggest about 14 Watts
              peak usage level
     IBM-PSG  ST318404LW, 18201 MB, 10k RPM, specs say peak operating
              draw, adding the +5V and +12V feeds, is 15.96 Watts
     SEAGATE  ST318404LW, 18201 MB: ditto

Intel L440GX+ motherboard:  difficult to estimate.  The motherboard
     specs say the maximum power _requirement_ is about 200W, which
     would include the power for two CPUs and maxed-out PCI slots.
     (I use one CPU and no slots, with two DIMM sockets occupied).
     Maximum rated power _requirement_ says little about power _usage_,
     other than being an absolute upper bound on it.

3 x 40 mm aftermarket (good) case fans:  total about 3 Watts
PSU overhead including PSU fan:  gosh, dunno, maybe 15 Watts

The three HDs draw about 45 Watts (peak).  Might be less, on avg.

My best guess is that the _rest_ of the system's about 50 Watts.
So, make that about 80-100 Watts system-total, at typical loading levels.
We can of course get a better figure using the Kill-A-Watt.

Hard drives

500GB SATA drives in 2.5" form factor tend to draw about 2.5 Watts
under load if running 5400 RPM, or maybe 3.0 Watts if running 7200 RPM.

(One needs to be very skeptical about manufacturers' power-draw figures,
because they tend to be based on extremely optimistic use of standby
modes, and there's probably a good bit of lying on top of that.  Note
that server-role machines cannot really use standby modes.)

Anyway, switching enzo from 3 x internal SCSI drives pulling 45 Watts to
2 x external SATA drives pulling 5-6 Watts would obviously help -- with
or without replacing the rest.


http://en.wikipedia.org/wiki/List_of_CPU_power_dissipation has
interesting figures -- omitting motherboard draw, case, draw, etc.

Intel Atom family:  ~2.4 Watts
Marvell ARM-derived embedded SoCs, recent models: ~3 Watts
PowerPC 750FX: 3.6 Watts
Intel Celeron family, recent models:  ~30 Watts
Intel PIII 600MHz: 34.5 Watts
Intel Core 2 Duo family, recent models: 35 Watts
Intel Celeron Dual-Core family, recent models:  35 W
AMD Sempron 64 3000+: 35 - 62 Watts, depending on chip
AMD Athlon 64 X2 family, recent models: 65-125 Watts, depending on speed
AMD Phenom 64 (multicore), recent models: 45-125 Watts, depending on speed
Intel Xeon ("server" CPUs), various recent models: 60-130 Watts,
   depending on speed and number of cores

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