Microwulf: Power Efficiency
Another way to measure a computer's
efficiency is its power efficiency,
where power is the computer's
electrical power consumption.
This is usually computed as the computer's
This is increasingly important,
as excess power consumption is inefficient,
consuming unnecessary energy and
generating waste heat, which can in turn decrease reliability.
We have metered Microwulf's power consumption:
Since Microwulf is only doing anything useful
when it is under load,
its power/performance ratio is 450 watts / 26.25 Gflops
= 17.14 watts/Gflop (under load).
At idle, it consumes 250 watts,
Under load, it consumes 450 watts,
While most clusters publicize their performance data,
Very few clusters publicize their power consumption data.
Some notable exceptions are:
an experimental blade cluster built at Los Alamos National Labs in 2002.
Green Destiny was built expressly to minimze power consumption,
using 240 Transmeta TM560 CPUs.
Green Destiny consumed 3.2 kilowatts and produced 101 Gflops
(on Linpack), yielding a power/performance ratio of 31 watts/Gflop.
Microwulf's 17.14 watts/Gflop is much better.
The (apparently defunct)
Multisystems DS-12 and DS-96 systems:
Microwulf's price/performance ratio
is much, much better than these commercial systems,
and its power/performance ratio is in the same ballpark.
The DS-12 "desktop" system consumed 170 watts under load,
and produced 13.8 Gflops (Linpack),
for a power/performance ratio of 12.31 watts/Gflop.
(The DS-12's list price was about $10,000,
making its price/performance ratio $724/Gflop.)
The DS-96 "under desk" system consumed 1580 watts under load,
and produced 109.4 Gflops (Linpack),
for a power/performance ratio of 14.44 watts/Gflop.
(The DS-96's list price was about $100,000,
making its price/performance ratio about $914/Gflop.)
Last, let's compare Microwulf with the machines on the list at
Entries on this list are machines from the
(which unfortunately excludes Microwulf),
ranked by the number megaflops they produce for each watt of power.
For Microwulf's 17.14 W/Gflop, this works out to:
1 / 17.14 W/Gflop * 1000 Mflops/Gflop= 58.34 Mflops/W
As of August 2007, Microwulf just surpasses the #2 Green500 machine
-- Mare Nostrum (58.23 Mflops/W) --
but well behind #1 BlueGene/L (112.24 Mflops/W).
Joel Adams >