[R] Yet another memory limit problem

[Tim Clark]

Dear List,

I have read and read and still don't get why I am getting a memory issue.  I am 
using a Samsung PC running Windows 7.  I have set memory in the target field:
 "C:\Program Files (x86)\R\R-2.11.1\bin\Rgui.exe" --max-mem-size=3G

But when I try a simple plot I get:

>   plot(mydat$Date,mydat$Time)
Error: cannot allocate vector of size 831.3 Mb
> memory.size()
[1] 2099.61
> memory.limit()
[1] 3583
> dim(mydat)
[1] 245   9

I would appreciate some help.  I think I set the target field correctly, both 
memory.size and memory.limit indicate I have over 2G of memory, yet I can't 
allocate 831.3Mb?  It just doesn't make sense to me.

Thanks,

Tim