"Seti Cruncher" <SetiCruncher@"NOSPAM"WildMail.com> wrote:

"Mike W" <Circle_314_And_Square_nospam@hotmail.com> wrote:

"Seti Cruncher" <SetiCruncher@"NOSPAM"WildMail.com> wrote:

Why do CPU temperatures spike (jump) when the SETI Client starts
a fresh work unit.  You would think the CPU temp and load would
be the same as when its mid way through a WU.

  Just curious,

It's my understanding, there are different stages to the processing
of a work-unit.  The first stage is highly intense for the CPU,
things settle into a rhythm after that.  I couldn't find a link
that's more specific, maybe somebody else has it or you've found
one on your own.

so far thats the best explanation I've seen yet for why CPU temps are
more intense at the begining of a work unit then at any other time.
I just though it was odd and thought I would ask, I know there are
some very knowledgeable folks in this NG and I've always enjoyed
learning from you's.

Found it!

"Let's look first at the most computationally intensive portion of the
calculation. The first job is to "de-chirp" the data

- that is, to remove all the effects of the doppler acceleration. At the
finest resolution, we have to do this a total of 20,000 times, from -10
Hz/sec to +10 Hz/sec in steps of .002 Hz/sec. At each chirp-rate, the 107
seconds of data is de-chirped and then divided into 8 blocks of 13.375
seconds each. Each 13.375 second block is then examined with a bandwidth of
.07 Hz for peaks (that's 131,072 tests (frequencies) per block per chirp
rate!)

This is a LOT of calculation! In this first step, you computer does about
200 billion calculations!"

http://setiathome.berkeley.edu/about_seti/about_seti_at_home_4.html

Mike