Subject: Re: CCL:A General Statement about Non-Intel x86 Processors

From: Michael Hodgson <[email-masked]>
Date: Tue, 31 Mar 1998 01:54:20 +0100 (BST)

> I think it is accurate to make the general statement that the AMD and
> Cyrix x86 processors cripple the floating point speed to enhance the
> integer and other instruction speed.

Not true at all.  While Cyrix chips may fall under this heading I have to
admit I know little about them.  AMD however are a different matter.  For
a single FP calculation (double presision) the K6 is actually on a par
with the Pentium Pro at least...  The differance is pipe-lining, something
that intels do and AMD's don't.  It really depends upon the job in
question and just how much fp there is involved.  With CHARMM for example
we found the K6 to be about 60% the speed of a pentium II (at the same
clock speed), but they are also a bit cheaper.  However the K6 is no
slower or even a bit quicker with graphics intesive stuff and windoze 95.

>  If the goal is floating point calculation speed, I would go with a 
> Pentium II.
 
I would however agree here, but for different reasons.  

1) Compilers, kernals etc, can often be optomised for a generation of
processor.  This means intel, as they largely control the standard.
(Based largely on linux observations)

2) Upgradability or "Future proofing".  Give your machine the longest life
you can.  If you buy pentium II the chances are your memory, HDD MB etc
will last for a number of years, and with intel promising 450+ cpu speeds
by the end of the year there is still a lot of expansion left in them.  If
you still need more power you can go for a duel processor machine, but
multiprocessors again means intel (they also have to be the same speed).
Going for a K6 however and you have to ask how much more can they get out
of socket 7 ?  Maybe 300Mhz, but that's gonna be one hot cpu :) 

3)  At the moment the bottom end of the pentium II market is really very
cheap indeed and you would not save much in buying AMD.  If you are
looking at upgrading a current system, then it's a different matter, but
buying new I think the PII wins every time on price/performance.

-Michael

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From: Krzysztof Radacki <[email-masked]>
Date: Wed, 08 Apr 1998 20:11:33 +0200

At 01:54 AM 31.03.1998 +0100, Michael Hodgson <[email-masked]> wrote:

 ...
 
>(Based largely on linux observations)

I'm supprised why anybody hasn't started to write additional code to g++ or
gc to have optimization for AMD K6 (writeing anybody I mean not specially
volunteers but more somebody from AMD Inc.).

           Krzys Radacki

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