Newsgroups: comp.sys.next
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!snorkelwacker.mit.edu!stanford.edu!neon.Stanford.EDU!calvin!zimmer
From: zimmer@calvin.stanford.edu (Andrew Zimmerman)
Subject: Memory
Message-ID: <1991Jun14.125927.18256@neon.Stanford.EDU>
Sender: news@neon.Stanford.EDU (USENET News System)
Organization: Stanford University
Date: Fri, 14 Jun 1991 12:59:27 GMT
Lines: 64

In article <SCOTT.91Jun14003836@mcs-server.gac.edu> scott@mcs-server.gac.edu (Scott Hess) writes:
>
>[ Lastly, some flamage.  Alot of people make fun of EPS (and
>  lately, myself) for our insistance that no matter the
>  raw performance of your CPU, you really are going to need
>  the memory and disk space.  Rather than attempt to argue,
>  as most apparently don't listen, I would advise anyone
>  who's doubtful to go out and find a NextStation400M
>  w/16M or 32M of memory, and a 105M machine with 8M, and
>  do a side-by-side comparison.  It will literally blow your
>  socks off.  We're not talking fractions of a second
>  differences here - in many cases, it's order of _magnitude_.
>  For instance, launch Edit on a file on the 105/8 machine.
>  Then, on the 400/16 machine.  The 400/16 is fast enough
>  that you really don't notice the launch time, while the 105/8
>  takes long enough that you start to get up to pace the room.
>  That's the difference between enjoying your time on the machine,
>  and spending it in frustration . . .]
>
>Later,
>scott hess                      scott@gac.edu

I would be interested in getting some hard numbers on how much faster a 
16 meg machine is compared to an 8 meg machine. Opinions that I have heard
range from "worlds of difference" to "doesn't help at all".  

I would guess that whether memory helps r doesn't help is largely a function
of how you have your machine set up and how you use your machine.

For example, I have a 200/8 standalone, an only run one or two apps at
a time with the Preference App hidden.  Launching an app can take between
5 and 15 seconds.  (The screen isn't large enough to run more then one or
two Apps at a time :-))

We have noticed that a 200/8 network machine tends to do a lot more swapping
to disk, and the Launch time is greater.  This machine was just upgraded
to a 200/16 (with parity).  The owner commented that he did not see that
great of speed improvement.

Launch time should mostly be a function of the hard disk speed (or network)
and the amount of memory that is being used for data.  The text (instruction)
memory should not be paged back to disk.  Relaunching a hidden App would
of course be faster if it had not been swapped out to memory.  Do the
people who notice a big speed increase tend to run many Apps at the same
time?  When you say "Launch", are you talking about the first launch, or
launching from a hidden state?

Please do not take the above comments to mean that I don't believe Scott and
EPS when they say that more memory helps.  I am considering purchasing more
memory, and want to know if it will make the machine respone that much faster.
As such, I would like to understand the context in which Scott and EPS are
making their claims.

****

BTW, if you really want to see a machine bog down, run mm.  I have heard
that when our DEC 3100s is running 4 copies of mm, it can take up to
30 seconds to read the mail.txt file.  That's on a machine with 24 Meg of
memory.  

***

Andrew
zimmer@calvin.stanford.edu
