processing speed

[Gary Stevens-2]

I'm about to buy a new computer.  Will an Intel Quad Core 2 processor run
SPSS 18 faster than a Dual Core 2?  I've read that the Quad processor is
wasted on programs not designed to handle it.  I'm working with files 450
columns wide by 2 million rows.  Most of the work is selecting data, cross
tabulations and custom tables.

What 32 bit computer configuration will run SPSS the fastest?  At some point
is the program itself the limiting factor?
I plan on getting 4gb RAM (the max I think with a 32 bit processor).

Many Thanks, Gary

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[Fry, Jonathan B.]

For selecting data, crosstabs, and custom tables, additional cores beyond two won't help much.  Those operations are not programmed to use more than one processor, and would not be much faster if they were.

What might help for a dataset of the size you describe is more memory.

If your typical .SAV file occupies 1GB, the operating system on a 4GB box will usually be able to keep the whole thing in memory from one data pass to the next.  That will make the second and subsequent passes much faster for the operations you describe.

If the OS can't keep an entire file in memory, it will discard the least-recently-used parts of it.  Since every data pass starts at the beginning of the file and reads it through to the end, the OS will always be discarding the wrong part unless it can keep it all in memory.  So if the OS can't keep the whole file in memory, it will have to reread from disk for each data pass; that is much slower than getting it from memory.

A 450 by 2 million dataset could occupy quite a bit more than 1GB; how much depends on the aggregate sizes of its string variables and its degree of compressibility.  You want your system's memory to be at least one or two gigabytes larger than any of your .SAV files.  That might require running a 64-bit operating system.  Most machines purchased now will run a 64-bit or 32-bit operating system.

Jonathan Fry
SPSS Inc.

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of Gary Stevens
Sent: Friday, October 16, 2009 12:41 PM
To: [hidden email]
Subject: processing speed

I'm about to buy a new computer.  Will an Intel Quad Core 2 processor run
SPSS 18 faster than a Dual Core 2?  I've read that the Quad processor is
wasted on programs not designed to handle it.  I'm working with files 450
columns wide by 2 million rows.  Most of the work is selecting data, cross
tabulations and custom tables.

What 32 bit computer configuration will run SPSS the fastest?  At some point
is the program itself the limiting factor?
I plan on getting 4gb RAM (the max I think with a 32 bit processor).

Many Thanks, Gary

=====================
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[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
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INFO REFCARD

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