Subject: Re: 486DX/40 or 486DX2/66?
To: None <Mark_Weaver@brown.edu>
From: Drew Hess <dhess@CS.Stanford.EDU>
List: current-users
Date: 04/09/1994 00:19:14
Mark_Weaver@brown.edu writes:
>
> Drew Hess <dhess@CS.Stanford.EDU> wrote:
> > Mark P. Gooderum writes:
> > >
> > > But on clock speed versus memory speed, remember that a 486 still isn't
> > > any where close to a RISC chip in cycles per instruction ratio.
> > >
> >
> >
> > Well, this is a topic for another place, but cycles/instruction is not
> > necessarily a good benchmark for comparing architectures-- especially
> > when comparing load/store (e.g. "RISC") architectures to register/memory
> > (e.g. x86) architectures.
>
> I think you missed the point. The point is: a high cycles per
> instruction ratio means that having the internal clock be twice as
> fast as the external clock is likely to make a big difference in
> overall performance.
>
>
No, I think you missed the point of *my* post. I took issue only with the
assertion that CPI has anything to do with the performance of the
i486 relative to a RISC machine.
I wasn't commenting on the post as a whole, just on the comparison of i486 CPI
vs. RISC CPI. That's why I said "this is a topic for another place"; that is,
because it wasn't relevant to NetBSD or the performance of variants of the
i486.
-dwh-
dhess@cs.stanford.edu
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