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From: jmunkki@kampi.hut.fi (Juri Munkki)
Newsgroups: comp.sys.next
Subject: Re: Floating point
Message-ID: <22833@santra.UUCP>
Date: 13 Jun 89 19:34:04 GMT
References: <89157.122728UH2@PSUVM> <680008@hpcuhc.HP.COM>
Sender: news@santra.UUCP
Reply-To: jmunkki@kampi.hut.fi.hut.fi (Juri Munkki)
Organization: Helsinki University of Technology, Finland
Lines: 28

In article <680008@hpcuhc.HP.COM> edwardm@hpcuhc.HP.COM (Edward McClanahan) writes:
>> MacII: 59 sec., NeXT: 21 sec., Sun 4/280: 8.7 sec., DecStation 3100:4.0sec.
>
>why was the NeXT (at 25MHz) so much faster than the MacII (at 15.67MHz)?

Reason #1:	The Mac II has two wait states.
Reason #2:	The Mac II has a 68020, the NeXT has a 68030.
Reason #3:	The Mac II has a 68881, the NeXT has a 68882.
		I assume this was a floating point benchmark.
Reason #4:	Most benchmarks are run directly after they
		have been ported. This means that the machine
		has all sorts of low level debuggers installed.
		As strange as it may seem, at least some versions
		of the MacsBug debugger reduce FPU performance
		by 50%. TMON does something similar, but not
		quite (try running Moire and see the difference)

Most people do not seem to be aware of #4, but even the first three
reasons should be enough to explain the difference under certain
conditions.

If you reply and your followup has nothing to do with NeXT, please
followup to comp.sys.mac.programmer...

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|     Juri Munkki jmunkki@hut.fi  jmunkki@fingate.bitnet        I Want   Ne   |
|     Helsinki University of Technology Computing Centre        My Own   XT   |
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