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Path: utzoo!utgpu!watserv1!watmath!att!rutgers!cs.utexas.edu!uunet!mcsun!ukc!tcdcs!swift.cs.tcd.ie!vax1.tcd.ie!rwallace
From: rwallace@vax1.tcd.ie
Newsgroups: comp.sys.m68k,comp.arch
Subject: Re: Moto's data predicts 68040 performance well below 20 MIPS
Message-ID: <6535.26a0e67f@vax1.tcd.ie>
Date: 15 Jul 90 21:56:14 GMT
References: <1990Jul13.163849.4282@msuinfo.cl.msu.edu>
Organization: Computer Laboratory, Trinity College Dublin
Lines: 18

In article <1990Jul13.163849.4282@msuinfo.cl.msu.edu>, fox@VIXEN.NSCL.MSU.EDU writes:
> 
> For much of the stuff we run, 16Mhz 68020 + 68881 runs at about .8 VAX
> mips. (Scientific technical applications). So it seems to me that
> 25Mhz could be no faster than 25/16 * .8 = 1.25 VAX mips.

Sounds like either we don't agree on what VAX MIPS mean or there's something
seriously wrong with your system or benchmarks. The 68000 at 8MHz is rated at
about .8 MIPS. The 68020 at 16MHz should run about 3-4 MIPS (factor of 2 for
the clock rate, factor of 2-3 for the better design). OK, processors run below
rated performance with depressing frequency for reasons like not enough cache
memory, badly written code etc. but by a factor of 4??? Are you sure you
weren't running a benchmark that proves your compiler produces code that only
runs 25% as fast as it should?

Russell Wallace, Trinity College, Dublin
rwallace@vax1.tcd.ie
"To summarize the summary of the summary: people are a problem"