Re: [R] 32 vs 64 bit

From: Prof Brian Ripley <>
Date: Thu 15 Dec 2005 - 10:02:04 EST

On Wed, 14 Dec 2005, Paul Gilbert wrote:

> I ran R on an AMD Athlon 64 with a 32 bit Linux (by accident, I moved
> the hard disk from another machine). Now, after install 64 bit Linux and
> 64 bit R, I am finding some of my R tests are quite a bit slower, I
> think because memory demands cause a lot of swap. Does anyone know if
> extra memory usage would be mainly because of R itself, or is there a
> lot of extra memory demand because of the OS, windowing system, and
> other apps?

There's a definite effect from R itself.

I never run a machine without plenty of RAM for everyday tasks but if you did, that could have a bigger effect on a 64-bit OS as all the applications are larger. (My 64-bit Opteron desktop has 2Gb, for example, whereas its 32-bit predecessor had 1Gb.)

This _is_ discussed in the R-admin manual (section 7 in R 2.2.0 in the version I just looked at). You can run 32-bit R on 64-bit Linux if you want for speed (and I sometimes do): this too is discussed in the manual.

Brian D. Ripley,        
Professor of Applied Statistics,
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Thu Dec 15 10:07:07 2005

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