Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!rochester!srs!matt
From: matt@srs.UUCP (Matt Goheen)
Newsgroups: comp.arch
Subject: Sun 4 MIPS rating
Message-ID: <941@srs.UUCP>
Date: 29 Jul 88 18:23:32 GMT
Reply-To: srs!matt@cs.rochester.edu (Matt Goheen)
Organization: S.R. Systems, Rochester NY
Lines: 39

I have always been led to believe that Sun's rating of the Sun 4/200
series as 10 MIPS to be "Vax" MIPS (this goes for the 7 MIPS 4/110
as well).  Well, it appears this this isn't the case.  In the most
recent issue of "Sun Technology", there is an article by Robert
Garner (one of the members of the SPARC development team).  Mr.
Garner uses the term "SPARC MIPS" when referring to the 10 MIPS
rating of the 4/200.  To make a comparison to the 3/200 series, he
states that the SPARC typically needs about 25% more instructions
to complete a given task than a 68020 does.  He rates the 3/200
series as 3.8 "MC68020 MIPS".  To make a speed comparison of the
3/200 to the 4/200, the following formula is used:

				10.0 MIPS
					Sun-4/200
	perf		= 0.8 * ----------------- = 2.0
	  4/200,3/200		3.8 MIPS
					Sun-3/200

Therefore, if we make the (poor) assumption that a 68020 MIPS is
about equal to a VAX MIPS, we get a rating of about 8.0 Vax MIPS
for the Sun 4/200 (we CAN say 8.0 MC68020 MIPS).  This contradicts
other articles I have seen published by Sun where the instruction
count to complete a given task is included in the MIPS calculation
(I believe one of these articles was in Sun's "A RISC Tutorial").

Using native MIPS ratings seems to be borderline dishonest as far
as I'm concerned.  Certainly the whole thing should have been
presented a bit more clearly.  Personally, I don't think anyone in
marketing should be allowed to write/print/think/say the word
"MIPS".

However, I must commend Sun on the publication of "Sun Technology"
(this Summer 1988 issue in particular).  There are quite a few
useful articles within it...

-- 
- uucp:		{rutgers,ames}!rochester!srs!matt	Matt Goheen 	-
- maybe-nets:	matt@srs.uucp OR matt%srs.uucp@harvard.harvard.edu	-
- 	"We had some good machines, but they don't work no more."	-