Is 4GB the max on a 32 bit OS?

[Jonathan D. Proulx]

On Thu, Jan 18, 2007 at 07:15:26AM -0500, Scott Ledyard wrote:
:On my list of "basic questions that I'm sure someone's answered, but I can't
:find it" is this:
:Can the x86 versions of Ubuntu (or any OS) employ more than 4GB of RAM?
:I read with interest how to size an LTSP server and noticed that people have
:recommended lots of RAM. But, I've also heard that a 32 bit processor cannot
:physically address more than 4GB of memory. True?

True and False....

you can custom build a 32bit kernel to address upto 64G of memory,
there is a performance hit but it's still much faster to use the lower
performing memory than to page to disk.

a single 32bit process however cannot address more than 4G of memory.

In the case where you need lots of memory to run lots of processes
this works out, in the case where you have a single process that wants
>4G it does not.

-Jon