Newsgroups: comp.sys.mac.hardware
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!ejb
From: ejb@think.com (Erik Bailey)
Subject: Re: IIsi RAM cache setting, performance...
Message-ID: <1991Jun12.152359.13065@Think.COM>
Sender: ejb@think.com
Organization: Thinking Machines Corporation, Cambridge MA, USA
References: <1991Jun11.161138.31376@kuhub.cc.ukans.edu>
Date: Wed, 12 Jun 91 15:23:59 GMT
Lines: 33

In article <1991Jun11.161138.31376@kuhub.cc.ukans.edu> barnhill@kuhub.cc.ukans.edu writes:
>	I understand that there was a posting somewhere about speeding up
>a IIsi by setting the RAM cache at a fairly high level, and wonder if anyone
>would be so kind as to fill me in?  
>	Thanks
>
>	db
>Dave Barnhill
>Barnhill@kuhub.cc.ukans.edu


I'd be happy to.  The trick is to set the RAM Cache to 768k [*].

In 256-color mode, the IIsi reserves 256k for video RAM.  The high (or low,
whichever it is) 1MB of RAM (where the video is) is, for some reason, slow.
When code is loaded into that memory bank, such as the Finder, a program,
whatever, the speed slows down.

However, the disk cache just happens to use that memory.  1MB - 256K = 768k,
so that is the setting you should use.  While I have not benchmarked the
speed improvement, it is enough that I now leave my IIsi in 256-color mode
in System 7, whereas it used to be in 16-color mode in System 6.0.7.

Good luck! --Erik

[*] It has been suggested that 384k may work almost as well as 768k, and
save you 384k in the process.  I have not tried this; your mileage may vary.

--
      Erik Bailey       | 7 Oak Knoll         | Thinking Machines Corp.
      ejb@think.com     | Arlington, MA 02174 | 245 First St.
      harvard!think!ejb | (617) 643-0732      | Cambridge, MA  02142
          /earth is 98% full. Please remove any excess inhabitants.
