Cheap PCs from Wal-Mart

Ken Chase math at
Mon Jun 2 22:40:09 EDT 2003

On Mon, Jun 02, 2003 at 03:25:47PM -0700, Jim Lux's all...
  >Which P4 and Athlon were you comparing..
  >I went to the linked page at Toms Hardware and found reasonably close results
  >Athlon XP 3200+, and P4 3GHz...
  >Now, what's the power consumption of those two?
  >I think the P4 dissipates a max of 85W (poking around on the same Tom's page)
  >The C3 at 800 MHz dissipates 6.65W average and peaks at 12W
  >The Nehemiah at 1 GHz dissipates 11.25/15 W ave/pk
  >So, looking at the scaling and comparing P4 against Via C3 Nehemiah
  >Speed 6809/1591  4.3:1
  >Power   85/15     5.7:1

I found slightly different numbers for the C3-Ezra-T 800:

(mind the spaces) C3 Ezra-T datasheet v1.0 .pdf

taking this to its pathological conclusion:

		C3 Ezra T-800	C3 Nehemiah 1Ghz	P4
heat dissip. W	5.0/8.5pk	11.25av/15pk		85 (peak or avg?)
dhrystones   d	1048		1591			6809
d/W		209/123		141/106			80
ratio		2.6 / 1.5	1.8 / 1.3		1

Now I dont know which power number to choose for the C3's - the power
ratings are listed as "average power dissipated while running Winstone 99 
on Win98" in the PDF. And there's no numbers there for the E10k-n (the
pdf link was off a June 2002 article from Tom's HW) for avg/peak power.

These numbers dont really mean that much, except in a very general sense.
Specific benchmarks and direct power usage readings would be much more
useful, considering:

- If you add a HD to the setup per CPU, you blow your total W/node figure
  (not to mention your price curve).

- I dont know what dhrystones are an accurate measure of what everyone is
  doing with clusters these days

- I dont know if what people do with clusters excercises average or peak
  power consumption for any CPU (or for some and not others).

(I do know that burnMMX and burnK7 running together would blow our
breakers for dual Tbird 1.3Ghz on Tyan 2460s with no HDs on 300W enermax
power supplies and 512Mb ram at 8 boards/15 Amps, where as running G98
or gromacs code did not, so what's running is relevant.)

Furthermore, it is to be noted that the E10K-n does require active cooling,
changing the amount of space required ('volume' for airflow must be included)
- though Im guessing that in a 'blade' type setup or with inline airflow over
big heatsinks, you could avoid fans onboard.

For computation power vs Watts, we should really be looking at the new
low-power celerons, I bet they have some figures competitive to the C3.


  >>         dhry    whet    mmi     mmf     memi    memf
  >>e800    1048    285     963     1588    194     208
  >>e10k    1300    351     1193    1968    233     245
  >>e10k-n  1591    366     2255    2285    664     389
  >>p4      6809    9327    22170   13896   5050    5041
  >>ath     3319    8855    13011   12217   2912    3080
  >>I think it's pretty clear that you need to expect much lower
  >>performance from even the 'high-end' VIA chips.  if your code
  >>more resembles dhrystone (mostly integer, cache friendly),
  >>then you can mostly expect to scale with clock speed, and the
  >>VIA chips might be attractive on a speed/(heat*cost) basis.
  >>for general clusters, where memory bandwidth and FP performance
  >>and integrated gigabit are big advantages, VIA doesn't compete.
  >>data is from the article above and
  >James Lux, P.E.
  >Spacecraft Telecommunications Section
  >Jet Propulsion Laboratory, Mail Stop 161-213
  >4800 Oak Grove Drive
  >Pasadena CA 91109
  >tel: (818)354-2075
  >fax: (818)393-6875
  >Beowulf mailing list, Beowulf at
  >To change your subscription (digest mode or unsubscribe) visit

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