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From: "Jonathan M. Bresler" <jmb>
Message-Id: <199606232020.NAA19050@freefall.freebsd.org>
Subject: Re: Mixing SIMMs of different speeds
To: nash@mcs.com
Date: Sun, 23 Jun 1996 13:20:22 -0700 (PDT)
Cc: freebsd-hardware@freebsd.org
In-Reply-To: <199606222041.PAA13207@zen.nash.org> from "Alex Nash" at Jun 22, 96 03:41:26 pm
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Alex Nash wrote:
> 
> I'm wondering if I can mix 60 and 70ns SIMMs.  Everyone says don't,
> but they don't say why.  I can understand not mixing SIMMs that will
> be accessed simultaneously (like banks 1 and 2), but why shouldn't it
> work when they are separated?  My motherboard's manual indicates 70ns
> or faster will work, so why wouldn't a mixture?
> 
> So I add 2 70ns SIMMs to the motherboard that had 60s in banks 1 and
> 2, and (not too surprisingly) strange things happened.
> 
> I removed the 60s and ran with just the 70s, it seems to be working
> great.
> 
> Now I'm starting to think, what if I ran with 70s in banks 1 & 2 and
> 60s in banks 3 & 4?  Since the motherboard runs with 70s ok, but the
> 60/70 mixture didn't work the first time, it must be able to determine
> the access speed.  Is the motherboard using bank 1 to determine what
> speed it should access memory with?  (This is a Tyan S1462 MB.)

	i have 2x4MB-70ns simms in bank0 and 2x4MB-60ns simms in bank1
	on an ASUS SP3G motherboard.  no problems at all.  systems was
	initially set up for 70ns simms.

jmb
--
Jonathan M. Bresler           FreeBSD Postmaster             jmb@FreeBSD.ORG
FreeBSD--4.4BSD Unix for PC clones, source included. http://www.freebsd.org/
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