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From: alan@pdn.UUCP
Newsgroups: comp.sys.mac
Subject: Re: Byte review. 386 v '020
Message-ID: <1311@pdn.UUCP>
Date: Sat, 12-Sep-87 15:05:31 EDT
Article-I.D.: pdn.1311
Posted: Sat Sep 12 15:05:31 1987
Date-Received: Tue, 15-Sep-87 01:40:43 EDT
References: <1376@imagen.UUCP> <116@faccs.UUCP> <509@sbcs.UUCP> <1179@pdn.UUCP> <2508@vdsvax.steinmetz.UUCP>
Reply-To: alan@pdn.UUCP (0000-Alan Lovejoy)
Organization: Paradyne Corporation, Largo, Florida
Lines: 48

In article <2508@vdsvax.steinmetz.UUCP> barnett@steinmetz.UUCP (Bruce G Barnett) writes:
/My figures are:
/
/	68020 @ 25MHz = 4 MIPS (Sun 3/200)
/	SPARC      = 10 MIPS (Sun 4)
/
/I believe you are saying:
/
/	68030 @ 30MHz = 16 MIPS ???
/
/I can only assume you literally have a 68031 chip NOW!?
/No fair jumping generations in a comparison.
/
/Otherwise I would like you to show documentation that the 68030 is a
/16 MIP CPU.

First of all, ANY chip could be a "16 MIP" CPU:  "MIP" means "Million 
Instructions Per ...".  Per what? Per Minute? Oh! You mean "Per Second!"
Well, that's MIPS.  The VAX 780 is generaly rated as 1 MIPS (NOT
MIP!!!).

Secondly, Sun (and various other sources) like to quote MIPS figures
as if the machine in question were a VAX.  VAXen get more work done
per instruction than most micropocessors (even m68030's) do.  According
to Motorola, the 68020 at 25MHz does 5-6 native MIPS, and the 68030
is (according to Motorola) "at least twice as fast as a 68020" at the
same clock cycle speed.  Therefore, at thirty MHz, it should run 4 times
as fast as a 68020 at 16 MHz -- provided the rest of the hardware in the
system with the '030 in it is designed to take advantage of the '030's
ability to do "burst mode" memory transfers, parallel address and data
bus activity, and the improved bus interface logic.  Simply plopping 
a '030 into a system designed for a '020 probably won't improve
things more than about 1.5x (at the same clock speed). 

Several weeks ago, benchmark figures comparing the Sun-3 to the Sun-4
were posted in comp.sys.sun.  These showed the Sun-4 to be about twice
the speed of the Sun-3 (25Mhz 68020).  The Sun-3 is NOT the fastest
68020 system, by the way.  Masscomp has a 68020 system that does almost 6000
Dhrystones/second (using the rather slow portable C compiler), while the
best the Sun-3 can do is somewhat over 4000.

Edge Computer has their own proprietary CMOS VLSI implementation of the
68010 that does 11 VAX-equivalent MIPS.  The cost is comparable to what
the RISC companies are charging for their CPUs.  (It's a board-level
product only that includes a generous amount of fast RAM and an operating
system license).

--alan@pdn