On Fri, 14 Jan 2005 16:43:51 +0000, John
<fredclark@consltec.demon.co.uk> wrote:

In article <34q3ffF4emjfiU1@individual.net>, Geoff
<fooooooool@hotmail.com> writes

Kerly2-Bill wrote:

Is it possible to run more than one copy of the S@H on one computer? I'm 
running Windows XP Pro, more than one hard drive, 512 Mb of
memory,

unless you have a cpu with hyperthreading (new p4) or more than 1 cpu there 
is no point running 2 clients at once 

Correct in your assertions! 

However, if your CPU has a 1+ Mb L3 cache then it is possible to run
multiple WUs at single WU speeds. 

It is generally reckoned that each WU can comfortably fit, and process
within a 512 Kb L3 cache. So, a 1 Mb L3 allows 2 WUs, and 2 Mb can
accommodate 3 - 4 WUs, etc.

One major advantage of the multiple WUs on CPUs with large L3 caches,
especially for AMD Athalons or Optrons, is there is no shared FSB and
RAM, unlike the Intel CPUs.

Certainly, my experience comes from using a dual P3, 933@933 and Win2K
Pro, and a dual Xeon, 2.8 Ghz with HT active on XP Pro.

The dual P3 will crunch a single average WU (0.417 AR) inside 7 hours.
When 2 WUs are crunched the time rises to 7.5 hours, due to the shared
bus and RAM.

This system should give 6.9 WUs per day but actually delivers 6.25.

A similar position can be seen on the dual Xeon:  

       1 WU takes 2.25 hrs to 2.5 hrs  =       10.7 to 9.6 WUs per day
       2 WUs take 3.25 hrs to 3.5 hrs  =       14.8 to 13.7 WUs per day
       4 WUs average 5.5 hrs           =       17.5 WUs per day 
                                               (actually 18+)

For a dual Optron @ 2.25 Ghz a WU should disappear every 1.25 - 1.5 hrs,
and both processors will produce the same result (no shared FSB or RAM).
Therefore this system will give -

       1 WU on a CPU           =       19.2 to 16 WUs per day
       2 WUs on 2 CPUs         =       38.4 to 32 WUs per day

Assuming the L3 cache per CPU is 1 Mb or more, then these figures could
be doubled. However, the system would be expensive, and 64 bit capable
with the right OS in time.

EVERYTHING you said is correct EXCEPT you meant to say L2 NOT L3.

I had my moms new laptop for a couple of weeks, testing it and loading
software etc, and it had a 1.6 Intel Centrino with a 2 meg L2 cache!!!
It would do 1 Classic unit in about 1 hour 40 minutes, when doing 1
unit at a time. When I cranked it up to 4 units at 1 time it slowed
down to almost 2 hours per unit.
I was running XP Home, CLI version of Classic, SetiDriver caching the
local units and SetiQueue caching the external units.
The switch over from a completed unit to getting and starting a new
unit took almost 2 minutes due to the lack of available onboard
memory, I think if I had lowered the units down to only 3 at a time
that would have been reduced. Networking was not an issue because it
was literally next to the router.
The machine had 512 meg of ram.