Re: [R] Memory available to 32-bit R app on 64-bit machine

From: Prof Brian Ripley <>
Date: Tue 27 Jun 2006 - 23:01:56 EST

On Tue, 27 Jun 2006, roger bos wrote:

> I want to get a 64-bit machine/OS system so I can put 16Gb of RAM in it. As
> first I assumed that I would have to use the 64-bit version of R to make use
> of the 16Gb of RAM, which would mean that I would use the Linux version of
> R. But I have heard many posters say they run the 32-bit version of R on a
> 64-bit machine/OS.

Yes, and the address-space limits on 32-bit applications still apply: it is done for speed.

> So my questions, in Windows 64-bit, how much memory
> would be available to the 32-bit R binary? Is it 4Gb (because its a 32-bit
> application) or 16Gb (because its being run on a 64-bit OS)?

2Gb, as it is a rather limited 32-bit subsystem of a 64-bit OS. See the reference in the rw-FAQ Q2.9 or ?"Memory-limits".

No 32-bit OS gives 4Gb address space to an application: most manage about 3Gb. See ?"Memory-limits" (which is tailored to the OS you are running).

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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 Tue Jun 27 23:10:39 2006

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