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From: siegel@endor.harvard.edu (Rich Siegel)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Apple is dumping 120ns SIMMS into SE/30s
Message-ID: <1463@husc6.harvard.edu>
Date: 2 Feb 90 13:04:16 GMT
References: <15@hite386.UUCP> <7852@hubcap.clemson.edu> <2827@draken.nada.kth.se>
Sender: news@husc6.harvard.edu
Reply-To: siegel@endor.UUCP (Rich Siegel)
Organization: Symantec Language Products Group
Lines: 38

In article <2827@draken.nada.kth.se> d88-jwa@nada.kth.se (Jon W{tte) writes:

>
>Nope !
>
>A 16 MHz machine will not run at all if the SIMMS are 120 ns, since
>the data won't be there when the CPU wants it.

	Nope! yourself. Your calculator may tell you one thing, that the
120ns rise time isn't fast enough to respond to the 16MHz bandwidth of the
processor, but the hardware designers and implementors at Apple would
beg to differ; the memory is accessed at one wait state, and accesses are
additionally bottlenecked by little things like bus arbitration.
>
>It _is_ bad of apple to put 120 ns SIMMS in a 16 MHz machine. Period.
>
	It would be if said 16MHz machine with 120ns memory didn't work,
but since thousands of Mac II's, IIx's, IIcx's, and SE/30's do work,
your assertion is empirically disproved.

	If you were correct, then my 40MHz Mac II which has 4x100ns and
4x120ns memory would not even start up.

R.



~~~~~~~~~~~~~~~
 Rich Siegel
 Staff Software Developer
 Symantec Corporation, Language Products Group
 Internet: siegel@endor.harvard.edu
 UUCP: ..harvard!endor!siegel

"When someone who makes four hundred and fifty dollars an hour wants to
tell you something for free, it's a good idea to listen."

~~~~~~~~~~~~~~~