Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mixcom!llvvll
From: llvvll@mixcom.COM (James R. Macak)
Newsgroups: comp.sys.mac.hardware
Subject: Re: What are the possible memory configurations of an SE/30?
Summary: More SE/30 SIMM details wanted
Message-ID: <625@mixcom.COM>
Date: 24 Apr 91 02:08:34 GMT
References: <1991Apr23.155150.7671@cec1.wustl.edu> <1991Apr23.181407.23784@magnus.acs.ohio-state.edu>
Distribution: na
Organization: MIX Communications, Milwaukee, WI (Worldwide Email, Usenet BBS)
Lines: 40

In article <1991Apr23.181407.23784@magnus.acs.ohio-state.edu> gaynor@magnus.ircc.ohio-state.edu (Jim Gaynor) writes:
>In article <1991Apr23.155150.7671@cec1.wustl.edu> bst2948@cec2.wustl.edu (Bryan Sauhsung Tung) writes:
>>	(several lines deleted)
>	(several lines deleted)
>The SE/30 has 2 bank of 4 slots each.  Each bank must be filled with
>SIMMs of the same size, and the really ought to be of the same speed
>as well.  The SE/30 requires a minimum memory speed of 120ns, which
>isn't difficult - most SIMM suppliers sell SIMMs that run at 70-80ns.

I've read this before about the SIMMs needing to be the same "speed" within a
bank, but never really understood the reason for this. Can someone post an
explanation (avoiding extreme techo-babble)? How much tolerance might be
acceptable relative to the speed difference? I have some 70ns SIMMs... need I
find some more 70ns or will 80ns do?

>Thus, with 256k SIMMs, 1MB SIMMs, and 4MB SIMMs, you have the
>following possible combos:

>Total RAM	Bank "A"		Bank "B"
>---------	--------		--------
>1 MB		4 256k SIMMs		-empty-
>2 MB		4 256k SIMMs		4 256k SIMMs
>4 MB		4 1MB SIMMs		-empty-
>5 MB		4 1MB SIMMs		4 256k SIMMs
>8 MB		4 1MB SIMMs		4 1MB SIMMs
>16 MB *		4 4MB SIMMs		-empty-

In the 5 meg configuration, does it matter if the 1 MB SIMMs are in bank "A"
or "B?" Might there be a speed degradation if the 256 K SIMMs were in one bank
or the other? I thought I had read something about this once upon a time...
(Note this is for a "straight" SE/30 without any card in its slot.)

Thanks.

Jim

-- 
macak@mixcom.UUCP (James R. Macak)          "I'm curious, Doctor, why is it
uunet!uwm!mixcom!macak                       called 'M-5' and not 'M-1'?"
<< All my own opinions. >>