Xref: utzoo comp.sys.mac:22405 comp.sys.mac.programmer:3020
Path: utzoo!utgpu!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!rutgers!cs.utexas.edu!ut-emx!nghiem
From: nghiem@ut-emx.UUCP (Alex Nghiem)
Newsgroups: comp.sys.mac,comp.sys.mac.programmer
Subject: Re: old and new RAM chips: which one is which
Summary: MacII use 120 nanosecond chips
Message-ID: <7590@ut-emx.UUCP>
Date: 3 Nov 88 04:16:34 GMT
References: <1014@osupyr.mast.ohio-state.edu>
Organization: The University of Texas at Austin, Austin, Texas
Lines: 26

In article <1014@osupyr.mast.ohio-state.edu>, pgn@osupyr.mast.ohio-state.edu (Paul G. Nevai) writes:

> Set #1 says:
> 
>      -12 TIH8817C9SN
>      TMS 4256FMC Singapore E
>      TM4256HU8
>      -12L 8817 SNK N4V0
> 
> Set #2 says:
> 
>      MH25608J -15
>      Japan 63410T
>      M5M4256J
>      63235A -15



Note that set 2 is has a marking of "15." Set 1 has a marking of "12"
These markings mean the speed of the chip.

12 stands for 120 nanoseconds. The Mac II needs these chips because
of it's higher microprocessor speed.

15 stands for 150 nanoseconds. Most microcomputer systems use 15 nanosecond
chips. 150 nanoseconds is appropriate for the Mac +, Mac SE, etc..