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From: avery@gestalt.Stanford.EDU (Avery Wang)
Subject: Re: Powerbook Duo Memory system -- SLOW
Message-ID: <1993Apr25.081733.14999@leland.Stanford.EDU>
Sender: news@leland.Stanford.EDU (Mr News)
Organization: DSO, Stanford University
References: <C5yJ3L.3LC@dartvax.dartmouth.edu>
Date: Sun, 25 Apr 93 08:17:33 GMT
Lines: 54

In article <C5yJ3L.3LC@dartvax.dartmouth.edu> Espen.H.Koht@dartmouth.edu  
(Espen H. Koht) writes:
> In article <1993Apr23.060059.7894@leland.Stanford.EDU>
> avery@gestalt.Stanford.EDU (Avery Wang) writes:
> 
> > Hi-
> > Do any of you hardware gurus out there know what kind of memory 
> > architecture Apple uses in the powerbook Duos?  Or in the powerbook
> > in general?
> > 
> > What are the factors that make the Duo 210 so slow compared to a desktop  
> > machine running the same processor at the same speed (25MHz 68030)?  How  
> > many wait states are in the memory system, etc?  What kind of a data 
> > bus does it use?  32-bit or 16-bit?  
> > 
> 
>    Huh?  Where did you get this idea from?  I think you got this
> backwards.  The Duo's memory is faster than its equivalent desktop
> machine by 5-10% (and the rest of the powerboks). I think the
> explanation for this was that it can refresh faster (in 2 instead of 5
> cycles I believe).  Things that could affect performance would be
> factors such as use of functions enhanced in the FPU (which the Duo
> doesn't have undocked).  Extensions and background applications can
> slow your computer down too.  Real life differences in speed are likely
> to be influence by the software you are running, what kind of screen
> depth you are running etc.
> 
> Espen
> 
> PS!  The Duo is 32-bit through-out.


Thanks for the enlightening post.  Is there a Technical Note on this?

The desktop machine I was referring to was actually not a Mac,
but rather, any of various workstations that use the
68030@25MHz, such as old Suns or old NeXTs.  I used to own a NeXT
68030 cube.   

But I will try rebooting without extensions to see what kind of
a speed difference I get with my powerbook Duo. I did notice an
extreme slowdown to unusability with a Mac Plus after
installing system 7 on it.  Why does the OS suck up so much CPU
power? 

Also, you're right--software does make a HUGE difference.  I
have the misfortune of using MS-Works on my Duo.  When editing
relatively small (40K) files, cut or copy takes several
seconds, often more than 6 seconds!!  This happens with power
cycling turned off.  As usual, MS software is maggot-infested
feces. 
I'm getting Nisus to replace it for my text editing.

-Avery
