Because both have different PCI devices? I think Janne's point is that:
Machine 1: 4096 - 3986 = 110 MB of memory mapped to PCI devices and unavailable to the OS Machine 2: 4096 - 3286 = 810 MB of memory mapped to PCI devices and unavailable to the OS You don't have Graphics Cards with a total of something like 768MB of Memory installed in Machine 2 do you? Of course if the machines are completely identical, then I have no idea. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:rhelv5-list- > [EMAIL PROTECTED] On Behalf Of solarflow99 > Sent: 24 September 2008 15:02 > To: Red Hat Enterprise Linux 5 (Tikanga) discussion mailing-list > Subject: Re: [rhelv5-list] PAE Kernel 32 bit RHEL 5.2 64GB RAM > > but why does 1 system show 3.2GB and the other 3.9? they both had 4GB > installed > > > > On Wed, Sep 24, 2008 at 2:59 PM, Janne Blomqvist <[EMAIL PROTECTED]> > wrote: > > > solarflow99 wrote: > > > that makes me wonder about something I have several computers > with 4GB of ram using the regular 32 bit kernel (non-PAE) and I see > different amounts of ram, for instance: > ]# free -m > total Mem: 3286 ]# > free -m > total Mem: 3986 > > > > Probably PCI device memory. They start at 4 GB and go downwards > (AFAIK most are not capable of 64-bit addressing so they have to be below > 4 GB). > > Now, many BIOS:es support "PCI hole remapping" (or whatever it's > called), meaning that the memory that gets clobbered by the PCI devices > can be remapped to somewhere beyond the 4 GB limit. However, obviously > you'll need PAE or x86-64 in order to access this remapped memory. > > -- > Janne Blomqvist > > _______________________________________________ > rhelv5-list mailing list > [email protected] > https://www.redhat.com/mailman/listinfo/rhelv5-list > > _______________________________________________ rhelv5-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv5-list
