Thread Subject: MATLAB suggesting 1 thread on multicore machine??

Hello all,

I'm working on machine with an Intel Core 2 Quad Q6600
processor. When I select "Enable Multithreaded Computation"
in Preferences, the "Automatic" suggestion is 1 thread. I
manually set it to 4, but when I run the demo program from
the help file, comparing 4 threads to 1, I get either no
change or decreased performance with the 4 threads.

I'm running MATLAB version R2007b

Any help is greatly appreciated.
Sky Pelletier

What is your operating system? Does your system see all four
cores? What happends when you set the number of threads with
maxNumCompThreads(4) ?

Greetings,
Sebastiaan

"Sebastiaan " <s.breedveld@erasmusmc.REMOVE.BOO.BOO.nl>
wrote in message <g2ca35$bak$1@fred.mathworks.com>...
> What is your operating system? Does your system see all four
> cores? What happends when you set the number of threads with
> maxNumCompThreads(4) ?
>
> Greetings,
> Sebastiaan

I'm running MS Windows XP Professional version 2002 service
pack 2

the OS sees all four cores.

I used the demo program multithreadedcomputations found in
the help files, which uses maxNumCompThreads to manually set
the number of threads to 2. I ran it using 2 and using 4
and both times the matrix multiply (the first benchmark it
runs) ran about .98 times as fast. Of the eight operations
it tests, only sqrt and .* were any faster, and they were
less than 1.25 times as fast as only using 1 thread...

Any ideas?

Thank you,
Sky