From: deal@hightop.nrl.navy.mil (Richard Deal)
Newsgroups: comp.sys.mac.misc
Subject: Re: Information on: The IIvi, IIvx, and Performa 600
Date: 17 Aug 92 19:50:14 GMT
Organization: Naval Research Labs (Washington DC)

In article <1992Aug16.210017.1816@risky.ecs.umass.edu> breck@ganzer.ecs.umass.edu writes:
 >Someone emailed to me (Liam Breck):
 >> You want to justify this? The si uses a 32 bit bus, not a 16 bit bus, so is
 >> about twice as fast. Same reason an SE/30 is twice as fast as an LCII. Also
 >> an LCII has max memory of 10MB. That doesn't leave much room for expansion.
 >> I have 8MB on my SE/30 right now and plan to go to 20MB in a month or so.
 >> I'd be pissed off if my machine maxed out at 10MB.
 >
 >This is a common misconception.  Actually, the IIsi is about 28%
 >faster, which is not enough to notice in most real-time applications.
 >When doing something very CPU-bound, you might notice.  That is to

This argument has been going on for some time now.  The fact is that
although in most real-time applications this speed difference may not be
enough to be noticed, in most REAL aplications it is.

 >say, if you usually complete a coffee break while compressing a large
 >archive with an LCII, you will have a bite of doughnut and sip of
 >coffee to go when the same task finishes on a IIsi.  :-) This 28%
 >difference in speed is mostly accounted for by the difference in
 >processor speed beetween the two machines -- 16MHz vs. 25MHz.  The
 >*IIci* is something like twice as fast as the LCII since it's clock
 >speed is 33MHz.  The bandwidth of the memory bus is really not
 >critical in personal computers, 'cause other bottlenecks hold things
 >up before the bus width does.  For instance, the 80386 is only 4%
 >faster than the 80386sx, which has a 16-bit external memory path.
 >It's the same in the case of the Macs; you'll find that the original
 >Mac II is only 4% faster than the original LC (both 020s at 16MHz).
 
I have a MacII with PMMU and FPU (not an option on the LC II) and it 
is VERY noticably faster than an LCII.  Don't even consider turning 
on vertual memmery on the LCII it turns in to a  r e a l   d o g.
All access times take twice as long on the LCII.  You can get some 
nice CPU upgrades for the LCII but you still have that 16bit bus.  
If you really don't have the money for the si then go for a SE/30
or a used mac.  I have seen macII's going for LCII prices.  With the
mac II you can get the FPU and PMMU (PMMU is part of the 68030 in the 
LCII but not FPU).  The LCII's are nice machines for wordprocessing.
Get something that you can upgrade or that will gep up for sometime
and the 16bit bus in the LC is going to hender it sooner rather than
latter.  I wouldn't go out an get a 286 system either no matter how
good of a deal it is (or how cheap a monitor you can get)  By the 
way with the mac II and one of the older 8bit display cards you can
make your own cable to use a TV as a display.   

 >Another point about video...  Since the LCII can use a low cost VGA
 >monitor (I got a Trinitron screen for $350) it really lets you save on
 >the monitor.  To get the same quality on a IIsi, expect to shell out
 >the bucks!
 >
 >The 10MB limit on the LCII's memory expansion is unfortunate, but not
 >unacceptable.  I have 8MB in mine, and run a whole heap of concurrent
 

-- 
#include <std/*>
The Butcher                  
Butch Deal                   deal@hightop.nrl.navy.mil
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