Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!north
From: north@Apple.COM (Donald N. North)
Newsgroups: comp.sys.mac
Subject: Re: Re: New RISC Graphics for Macs (and other Quest's)
Message-ID: <39788@apple.Apple.COM>
Date: 23 Mar 90 22:36:38 GMT
References: <22297@watdragon.waterloo.edu> <5360046@hpccc.HP.COM>
Organization: Apple Computer, Inc.
Lines: 21

In article <5360046@hpccc.HP.COM> dlw@hpccc.HP.COM (David Williams) writes:
>>>After looking at the product blurb with a photo of the motherboard, I can
>>>assure you the SIMMs in the IIfx are 64 pinners.
>>>I think it has to do with the fact that the previous SIMMs don't have enough
>>>pins to go above 4 Megs, and they want the IIfx to handle 16 meg SIMMs when
>>>they come out.
>>All 30-pin simms have 12 address bits, which allow 16Meg chips. The 64 pinners
>>allow separate data-in & out lines, for dummp&run writes
>I'm STILL confused...does this mean I can use 80ns simms like the ones
>I now have in my IIx[from Peripheral Outlet] in a IIfx or are the
>simms custom jobbies available ONLY from APPLE? Are "normal" 80ns
>simms 64 pinners? I mean how would one specify the correct simms when
>ordering from a simm supplier?

The IIfx uses a new 64-pin SIMM form factor which is *INCOMPATIBLE* with
all previous MacPlus/SE/SE30/II/IIx/IIcx/IIci 30-pin SIMMs.  This was done
for performance-related reasons in the design of the machine.

For now, I believe Apple is the only source of these parts; but I expect
that third-party memory vendors are designing new SIMM modules as I type
this.