On Tue, Aug 28, 2012 at 1:34 AM, Bob Proulx <b...@proulx.com> wrote: > Stephen Powell wrote: >> By the way, there's something I don't understand. A 32-bit processor can >> only access 4G of "real" (extended) memory, right? So why are there >> motherboards available for 32-bit processors that support installing >> more than 4G of RAM? What good is memory that the processor can't address? > > With PAE (physical address extensions) the processor *can* address > more than 4G of ram. A single process is still limited to 32-bits > which usually works out effectively to 3G of ram but the operating > system can make use of more than this. It can be used for filesystem > buffer cache and for multiple 3G programs. A machine with 6G of ram > for example could run two 3G program at the same time and hold them > both in memory without swapping. Or run one 3G program and still have > 3G for the system to use in filesystem buffer cache. With PAE having > more than 4G of memory is quite useful. > > Using PAE does have a small performance impact. It slows things down > by 2%-3% in my use cases. But the increase in ram for buffers usually > more than makes up for the differences. >
iirc, pae is only 48 bits too. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/CAH_OBifAaW=m2tqojv6ksybnbp2bqecm1cf4fy8c9y9aqzk...@mail.gmail.com
