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From: gillies@m.cs.uiuc.edu
Newsgroups: comp.arch
Subject: Re: Moto's data predicts 68040 performa
Message-ID: <3300154@m.cs.uiuc.edu>
Date: 15 Jul 90 23:28:00 GMT
References: <40088@mips.mips.COM>
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Nf-ID: #R:mips.mips.COM:40088:m.cs.uiuc.edu:3300154:000:921
Nf-From: m.cs.uiuc.edu!gillies    Jul 15 18:28:00 1990


> So, the data and the claim that 68040==20VAXmips  implies that the earlier
> 68020 has a "sustained performance level of 4.9 VAX-equivalent MIPS"
> (4.9 = 20/4.1).  Does anybody seriously believe this?

I thought that originally, a VAX-mip (= speed of Vax 11/780 on j
random code) was .4 million instructions per second (.4 "native mips"
?).  This would put the 68020 at 4.9*.4 ~ 2.0 "native mips".  This is
a widely quoted figure (2-3 mips) for the 68020, and believable for a
16Mhz system, judging from cycle counts in the motorola manual.

On the other hand, a VAX-mip is an 11/780 mip, isn't it?  A VUP is
something entirely different, based on microvaxes, n'est-ce pas?

disclaimer:  This may be completely wrong, please don't flame me.

Don W. Gillies, Dept. of Computer Science, University of Illinois
1304 W. Springfield, Urbana, Ill 61801      
ARPA: gillies@cs.uiuc.edu   UUCP: {uunet,harvard}!uiucdcs!gillies