Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!psuvax1!psuvm!gfx
From: GFX@psuvm.psu.edu
Newsgroups: comp.sys.mac.hardware
Subject: Re: IIci + 8Mb != more speed
Message-ID: <90045.004806GFX@PSUVM.BITNET>
Date: 14 Feb 90 05:48:06 GMT
References: <22499@mimsy.umd.edu> <25d88b45.2cea@polyslo.CalPoly.EDU>
 <22513@mimsy.umd.edu>
Distribution: usa
Organization: Penn State University
Lines: 46

Here's the theory:

In article <22513@mimsy.umd.edu>, folta@tove.umd.edu (Wayne Folta) says:
>
>In article <25d88b45.2cea@polyslo.CalPoly.EDU>, rcfische@polyslo.CalPoly.EDU
>(Raymond C. Fischer) says:
>
>>By running your programs IN bank B memory, your avoid contention with
>>the video.  The processor runs from bank B and the video from bank A.
>>However, the Mac still loads programs into RAM from the bottom upward.
>>Thus, on an 8 meg machine, your program is probably still running in
>>the lower 4 meg (i.e., bank A).  If you can get it to run in bank B,
>>then you should see a speedup.  This is also why 5meg is such an
>>attractive configuration for the IIci.  1meg in bank A is usually
>>used up by the video and system leaving only the 4 meg in bank B for
>>running programs.
>
>I forgot to mention that I was running under MultiFinder in System 6.0.4.
>I have heard it claimed that MultiFinder will automatically run stuff as
>high in memory as possible, so I assumed that I was in Bank B.  I also
>shrunk LISP's memory down to 1500Kb before I ran it, guaranteeing it
>didn't wrap around into Bank A.
>

Here's some data:


I ran MacSpeed (available from sumex-aim) to see what happens.  I have a
IIci / 8 Megs / Rodime 100i.  I tried loading MacSpeed first ("low RAM")
or above other applications totalling 6+Megs ("high RAM").  I have also
tested the impact of the video setting: 1-bit BW and 8-bit color.  The
results are below.  The numbers are standardized to the speed of a Mac SE.
i.e. CPU of IIci, high RAM 8-bit video, runs 5.96 times faster than an SE.
The results show minimal improvement wrt speed when you run 1-bit video.  But
if you have 8 Megs, applications in high RAM run as fast in "full" color
as they would in BW.  If you have 4 Megs or less, CPU slows down by 20%.
INITs/CDEVs have a negligible impact on this benchmark.  Would be interesting
to see the results on a machine fitted with a video card.  Stephane


          Set-up            CPU     Co-Processor        Disk
       1-bit / low RAM      5.8        12.16            3.25
       8-bit / low RAM      4.72        9.84            3.10

       1-bit / high RAM     5.97       12.39            3.24
       8-bit / high RAM     5.96       12.39            3.23