Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!pasteur!eris!korn
From: korn@eris.berkeley.edu (Peter "Arrgh" Korn)
Newsgroups: comp.sys.mac
Subject: Re: Mac IIx vs. Dove 68030 upgrades; PC boards for SIMMs?
Message-ID: <6041@pasteur.Berkeley.EDU>
Date: 30 Sep 88 02:54:37 GMT
References: <16327@shemp.CS.UCLA.EDU>
Sender: news@pasteur.Berkeley.EDU
Organization: What, me organized???
Lines: 36

In <16327@shemp.CS.UCLA.EDU>, korfhage@CS.UCLA.EDU (Willard Korfhage) said:  
>
>   I have been keeping tabs on 68030 upgrades and coprocessors for the Mac,
>some information I just got from Dove makes for an interesting comparison
>with the recent Apple prices. They are making something to replace the 68020
>in a II with a 68030 running at 20 Mhz ($999), 25 Mhz ($1299), or
>33 Mhz ($1599). Supposed to ship in mid-October.
>   What I wonder, though, is just how much performance you can get from the
>faster clock speed, given that most macs have 120 ns rams? I asked about this,
>and was told that the 25 and 33 Mhz models would run with 1 wait state using
>120 ns memory, and 0 wait states with 100 or 80 ns memory. Is there anyone
>out there with some 68030 hardware knowledge who can say if this is
>reasonable? I though that Mac II's had two wait states built in (it may only
>be one). If they do change the wait states for RAM access, does that mean
>they have to modify the logic board for the upgrade?...

I believe that the Dove upgrade has space on their 'daughter-board' that
slips into the 68020 & 68851 & 68881 sockets for SIMM strips.  In this
way their processor would talk directly to the RAM over their own bus,
rather than the Mac bus.  I don't know if they require that you put RAM
on this daughter board (and if it's there, whether cards can access it for
DMA-related operations).

I looked at doing this sort of thing a few months ago, and the conclusion 
I came to was that the only way to get any real performance increase was
w/a daughterboard (the ~15% increase of the IIx isn't a 'real' increase worth
writing home about [though a press-release is another matter...]).

Anyone from Dove on the net?

Peter

--
Peter "Arrgh" Korn
korn@ucbvax.Berkeley.EDU
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