[R] Maximum amount of memory

[Tim Cutts]

On 21 Mar 2005, at 4:42 pm, marvena at tin.it wrote:

> Hi,
> I have a problem:I need to use the maximum amount of memory in order to
> perform a very tough analysis. By purchasing the suitable computer, 
> what's
> the maximum amount of memory obtainable in R?

Assuming that R is happy to use 64-bit memory pointers, the limit will 
be your wallet.  You could buy an SGI Altix and just keep buying more 
and more memory for it.  I don't know the limit - I know that SGI have 
sold one machine in Japan with 13 terabytes of memory.  We have two of 
them here with 192 GB of RAM each, but I haven't tried R on them yet - 
they're used for other things.

Whether such a course of action is sensible is another matter.  Large 
memory machines rapidly become *extremely* expensive; once you have to 
use DIMMs larger than 1GB each, the price becomes prohibitive.  
Consider spending the same amount of money on employing several 
programmers and/or statisticians to break your problem down into 
smaller tasks than are tractable on smaller machines.

Our 192 GB machine cost quite a lot more than 192 desktop PCs with 1GB 
of RAM each.  In fact, the memory becomes so expensive the rest of the 
machine is virtually free, in comparison.  :-)

If you can get away with more modest amounts of memory, then a machine 
like the HP DL-585 might suit you - a quad processor Opteron, which can 
take up to 32GB or so of memory.  Fairly modest price.

Tim

-- 
Dr Tim Cutts
Informatics Systems Group, Wellcome Trust Sanger Institute
GPG: 1024D/E3134233 FE3D 6C73 BBD6 726A A3F5  860B 3CDD 3F56 E313 4233