Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ames!apple!dwells
From: dwells@Apple.COM (Dave Wells)
Newsgroups: comp.sys.mac
Subject: Re: Nix on mixing memory speeds?
Message-ID: <34977@apple.Apple.COM>
Date: 23 Sep 89 22:04:20 GMT
References: <11979@cit-vax.Caltech.Edu> <4002@phri.UUCP> <2040@leah.Albany.Edu> <11900@polya.Stanford.EDU>
Distribution: usa
Organization: Apple Computer Inc, Cupertino, CA
Lines: 32

In article <11900@polya.Stanford.EDU> kaufman@Neon.Stanford.EDU (Marc T. Kaufman) writes:
>I rise to Roy Smith's defense.  That IS a constructive comment -- to the
>effect that: the folklore that says you can't mix memory speeds (subject to
>the requirement that each memory module is itself adequately fast) -- is
>Bullshit.
>
>Now I know that one doesn't have to be an EE to own and operate a computer.
>But we don't have to be afraid of them, either.  There is a lot of tolerance
>in the design of a computer just so spot shortages of a particular chip, or
>a low-tolerance part, won't make the machine unbuildable.  That's why so many
>(IBM) clone makers can push nominal 16 MHz machines to 20MHz -- as long as
>you don't get them too hot.
>
>If you want to cause trouble, why don't we start the rumor that using faster
>memory chips will invalidate the FCC clearance because the faster rise times
>radiate more...

It is possible for mixed speed RAM in a bank to cause malfunctions.  In a
former life I was in tech support for a small accelerator company.  While
I was there, we discovered that combinations of different speed (and sometimes
manufacturer) RAM would cause the Mac to go out to lunch.  This wasn't a
one time incident, and all of the RAM in use was rated at or above spec.  The
Mac's would occassionally die when we mixed some brands/speeds of RAM within
banks. (Hey, don't worry.  I'm not an EE  ;-]  )

-Dave

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           Dave Wells, Apple Computer, Inc.  MS: 37-Y  (408) 974-5515
          Mail: dwells@apple.com or AppleLink d.wells or GEnie D.WELLS
 These opinions may be nothing more than the ramblings of a fatigued tinkerer
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