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From: GUBBINS@RADC-TOPS20.ARPA
Newsgroups: net.micro.amiga
Subject: Re: Another ST-AMIGA comparison
Message-ID: <3818@topaz.RUTGERS.EDU>
Date: Fri, 27-Sep-85 17:01:24 EDT
Article-I.D.: topaz.3818
Posted: Fri Sep 27 17:01:24 1985
Date-Received: Tue, 1-Oct-85 10:39:26 EDT
Sender: daemon@topaz.RUTGERS.EDU
Organization: Rutgers Univ., New Brunswick, N.J.
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From: Gern 

I believe that the Amiga uses 64Kx4 chips so that the 68000 can perform
a 16-bit data path memory access while the machine only has 256K of memory
(in 8 chips).  If the Amiga had eight 256Kx1 chips, it could not do a
16-bit memory access without extra circuits/extra cycles to do a 8-bit
twice multiplexedfetch.   Hence, using 64Kx4 256K-bit chips, it can
hit four of these 8 chips at once to perform 16-bit and still have 256Kbytes
of memory (taking up only 8 chips).

The Atari 520ST, I believe, has to trash the 130?ST because they were using
the 256Kx1 and the extra circuitry was too much.  Hence, only a 512Kbyte
machine is available with 16 256Kx1 chips (hitting all 16 chips for a 16-bit
operation.

Cheers,
Gern
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