[R] Memory in R on windows running 64bit XP

[michael watson (IAH-C)]

Hi
I'm running 32-bit R on Windows XP 64bit and the machine has 16Gb of RAM. The help for memory.limit states:

If 32-bit R is run on some 64-bit versions of Windows the maximum value of obtainable memory is just under 4GB.

So, using the help which states the size parameter can go up to 4095:

memory.limit(size=4095)

When I run mclust I get:

Error: cannot allocate vector of size 1.3 Gb

So, now I set the max-mem-size flag:

--max-mem-size=3500M

Repeat and I still get the same error:

Error: cannot allocate vector of size 1.3 Gb

So, can anyone help?  32 bit R is reported to be able to use up to 4Gb of RAM on 64 bit windows, yet mine croaks at 1.3Gb.

> sessionInfo()
R version 2.9.2 (2009-08-24)
i386-pc-mingw32
locale:
LC_COLLATE=English_United Kingdom.1252;LC_CTYPE=English_United Kingdom.1252;LC_MONETARY=English_United Kingdom.1252;LC_NUMERIC=C;LC_TIME=English_United Kingdom.1252
attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base
other attached packages:
[1] mclust_3.3.1

Thanks
Mick