From owner-freebsd-hardware Sat Jun 22 15:39:51 1996 Return-Path: owner-hardware Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id PAA13982 for hardware-outgoing; Sat, 22 Jun 1996 15:39:51 -0700 (PDT) Received: from zen.nash.org (nash.pr.mcs.net [204.95.47.72]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id PAA13963 for ; Sat, 22 Jun 1996 15:39:46 -0700 (PDT) Received: (from alex@localhost) by zen.nash.org (8.7.5/8.6.12) id RAA22378; Sat, 22 Jun 1996 17:38:28 -0500 (CDT) Date: Sat, 22 Jun 1996 17:38:28 -0500 (CDT) Message-Id: <199606222238.RAA22378@zen.nash.org> From: Alex Nash To: michaelv@HeadCandy.com Cc: freebsd-hardware@freebsd.org Subject: Re: Mixing SIMMs of different speeds Reply-to: nash@mcs.com Sender: owner-hardware@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > >Aren't both banks (1&2) accessed simultaneously for any 32-bit access? > >When you said all slots, you mean groups of two, right? > > I was going under the assumption that one "bank" consists of the > smallest usable memory size, i. e. two 72-pin SIMMs. So, bank 1 is > the first pair of SIMMs, bank 2 the second.... Sorry, I got my terminology backwards :) > >> If it were going to work at all, that would be my suggestion: put the > >> slower memory first, so if it does some sort of test to see how fast > >> your memory is, it might use the slower memory for the timings. Note > >> that this is highly speculative and implementation specific. Only the > >> people who designed your motherboard can tell you for sure. > > >Good, so I'm not crazy for thinking this might work :) > Right -- this is what I would expect. But there's still no guarantee. > Some engineer may have found it more useful to test, say, the last > SIMM installed. How can we know without asking him? I accept that there's no guarantee, but knowing programmers, the extra effort required to figure out which is the last bank would probably be passed up in favor of a hard coded get_ram_speed(0) :) Alex