Sparc32 systems and power consumption

["Bruce O'Neel" <linux@pckswarms.ch>]

Hi,

I have both a collection of sparc32 systems (2x SS20s, 2x SS5/170s, 1x SS4) and 
a very strong interest in low power in systems that run 24/7.

As a result I've done some power measurements on them in order to find the lowest 
power system that will do what I need.

(All of the below should have "In my experience/with my measurements/etc" stuck
in front).

I don't see any important power consumption difference whether the systems
are idle or not. I actually see a decrease when I use a new fast scsi disk
vs the old 1 and 2 gig disks these came with from Sun.  In all cases they
are maxed out in memory as well so that draws some extra.  Finally, this is at 
220V so the power supplies might be more or less efficient at 110V.  In some
cases I've used the SS4 50 watt power supplies and in other cases I've used
the SS20 150watt power supplies and I don't see much difference in consumption
between these two power supplies in terms of efficiency.  My guess is that 
these power supplies aren't so efficient in converting power.

>From lowest to highest, measurements taken at the power plug.
 
SS4/110                     60watts
SS5/170                     65watts
SS20/Dual 100 hypersparc    75watts
SS20/180 Hypersparc         77watts
SS20/Dual 55 hypersparc     80watts
SS20/60 Supersparc          80watts
SS20/85 SuperSparcII        80watts
SS20/133 hypersparc         85watts
SS20/200 hypersparc         90watts
SS20/Dual 90 hypersparc     90watts
SS20/Dual 142 hypersparc   115watts

For the benchmark I was running when doing this test, to round numbers,
the speed scaled with the clock speed.  

In general these systems were running NetBSD, but, Debian Sarge
was used on the SS4 and the SS20s with SuperSparcs as well with 
no major changes in power usage.

Just a few other numbers with newer systems:

300mhz Ultra10             90watts
Mac 7300/200              100watts (two disks though)
Dual 400mhz Ultra2        180watts (two disks though)

I am a big SPARC/PPC fan and not a big x86 fan, therefore I was quite 
disapointed to find a cheap Dell 500mhz PIII drawing only 55 watts or so.  
So, 2x faster than the Ultra 10 and 1/2 the power (round numbers).


As someone else pointed out though, a NSLU2 is very very low power
(my watt meter doesn't measure it).  It's even lower power than some
cheap 8 port Netgear switch (at 11 watts). The house server is a 
NSLU2 because of that.

cheers

bruce