shawn wilson <[email protected]> writes: > On Tue, Aug 28, 2012 at 1:34 AM, Bob Proulx <[email protected]> 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.
"only" meaning 256 terabytes in this case... I'll be very surprised to ever see a 32 bit processor that can make effective use of that much memory. -- "Erwin, have you seen the cat?" -- Mrs. Shroedinger -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/[email protected]
