On Wed, Jul 18, 2001 at 05:04:45PM +0100, Jonathan Belson wrote:
> > > i have an intel 4400 platform equipped with 4 xeon processors and 6G ram.
> > > the mainboard is based on the ServerWorks ServerSet II HE chipset (by
> > > intel), which supports up to 16G RAM (or 32G, i'm not sure at the moment).
> > >
> > > i have installed FreeBSD 4.3-STABLE.
> > >
> > > unfortunately, the system seems unable to work with this amount of ram.
> > FreeBSD does not support more than 4G RAM (at least not on x86, I
> > don't know about Alpha).
> > My suggestion would be to remove the extra 2G RAM from the machine and
> > see if things work better then. (FreeBSD will not be able to use it
> > anyway so you don't lose anything by removing it.)
> Dumb question: by my calculations, a 32bit address register can only
> address 2**32 bytes of memory, ie. 4GB. Is it possible for your
> average P3/Athlon to addres more than this? Does it use banking/
> MMU tricks?
Not a dumb question but yes, and yes.
Modern x86 CPUs can address more than 4 GB of physical RAM.
I think this was introduced with the Pentium Pro but I am not certain.
Yes, it uses MMU tricks to do it.
Note that even though the physical memory may be more than 4 GB the
address space of a single process is still only 32 bits so a single
process still cannot address more than 4 GB of RAM.
<Insert your favourite quote here.>
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