Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!pacific.mps.ohio-state.edu!linac!mp.cs.niu.edu!ux1.cso.uiuc.edu!midway!quads.uchicago.edu!jcav
From: jcav@quads.uchicago.edu (john  cavallino)
Newsgroups: comp.sys.mac.hardware
Subject: Re: The LC vs. IIsi (LONG)
Message-ID: <1991Jun7.214930.9822@midway.uchicago.edu>
Date: 7 Jun 91 21:49:30 GMT
References: <1991Jun5.175401.14345@sequent.com> <1991Jun7.192453.11305@dartvax.dartmouth.edu>
Sender: news@midway.uchicago.edu (NewsMistress)
Organization: University of Chicago
Lines: 45

In article <1991Jun7.192453.11305@dartvax.dartmouth.edu> Brian.V.Hughes@dartmouth.edu (Brian V. Hughes) writes:
>In article <1991Jun5.175401.14345@sequent.com>
>lff@sequent.com (Lou Fernandez) writes:
>    In terms of speed requirements, I wouldn't put anything slower that
>80 Ns in any of the  newer Macs.

The Apple specs say that the LC needs 120ns and the IIsi needs 100ns.

>> 2) Video performance
>
>    The LC has the superior on board video capabilities, because the
>screen image is stored in a special Video Ram SIMM. The IISi stores the
>video image in physical RAM and can, when running in 256 color mode,
>cause certain functions to happen slower than normal. As with all Macs
>that have color, you can use the Monitors cdev to run in 1 bit (B&W)
>mode. It is also possible to upgrade the LC Video Ram from the stadard
>256k SIMM to a 512K SIMM giving the same video performace that you have
>with a stock IISi, and if you have the 12" RGB monitor you will have 16
>bit(32,000) color.

Quibble: The LC cannot drive the Portrait and 2-Page monitors (no matter
how much VRAM there is), while the IIsi can.

>> Are there other important functional differences between the LC and the
>> IIsi?  Which of these might prevent some software which I buy in the
>> future from running on the LC?
>
>    Functional differences... Well the IIsi, is a mac II the LC isn't.
>That ,means that you must use the on/off switch in the back to turn the
>LC off, instead of having shut down do all the work for you. Other than
>that the only other real difference is the fact that the LC is a 16 mHz
>68020, and the IIsi is a 20 mHz 68030. There is a substantial
>performance difference between the two chips that goes beyond just the
>clock speeds.

The main reason for the LC's slower speed is that the 68020 is connected to a
16-bit data bus (which, BTW, is the real reason you replace its SIMMs in groups
of two)


-- 
John Cavallino                      |     EMail: jcav@midway.uchicago.edu
University of Chicago Hospitals     |    USMail: 5841 S. Maryland Ave, Box 145
Office of Facilities Management     |            Chicago, IL  60637
B0 f++ c+ g+ k s+(+) e+ h- pv (qv)  | Telephone: 312-702-6900