Joe Devlin wrote:
> BTW, multi-processor machines don't necessary help much because Matlab
> isn't setup to take advantage of multi-threaded environments yet. So
> a single process can only use one processor. Of course, if you have
> multiple SPM sessions running then a multi-processor system will help.
>
Just to add to Joe's Comments, we're using SunUltra boxes, and have
found the performance of the dual-processor (an Ultra 2 and an Ultra60)
machines to be noticably faster than the single-processor ones, with all
other factors help constant (RAM, chip speed, disk access, etc). While
it's true that MATLAB will only use 1 processor, it will use that
processor to the maximum that it can. Our guess is that having the extra
CPU speeds things up because all the other things that the system wants to
do (OS stuff, window managers, any other programs you're running, etc) can
use the second chip, and MATLAB can hog all of the power of the other.
Another recommendation for significantly enhanced performance is to use
a server-workstation setup, where you run your X session etc. on a
workstation (which is comparatively cheap, you can even use cheapo linux
boxes if you're willing to maintain both Linux & Solaris systems), and
then run your SPM and other analysis jobs remotely on the compute server.
This frees up the CPU on the server for computation, while relieving it of
the load of running a window manager (which can hog a lot of RAM as well),
and anything else you may be doing while you wait for SPM to finish
normalizing or whatever.
And let me reiterate what Joe said about RAM - the more, the better. If
you have to start swapping to disk, performace goes WAY down.
Best of luck,
-- Aaron
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Aaron J Newman 'Always the beautiful
Brain Development Lab answer
Dept of Psychology that asks a more beautiful
University of Oregon question.'
Eugene, OR, USA 97403-1227 - e.e. cummings
(541)346-4889
fax:(541)346-4271 http://www.uoregon.edu/~anewman
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