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From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.unix.amiga
Subject: Re: Amiga 3000UX, X, OpenLook, Motif, Color, A2410, Etc. (somewhat long)
Keywords: Amiga 3000UX, X, OpenLook, Motif, Color, A2410, etc.
Message-ID: <19928@cbmvax.commodore.com>
Date: 16 Mar 91 04:55:43 GMT
References: <392@tcr.UUCP> <19887@cbmvax.commodore.com> <1991Mar15.063527.595@kessner.denver.co.us>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 36

In article <1991Mar15.063527.595@kessner.denver.co.us> david@kessner.denver.co.us (David D. Kessner) writes:
>I know that this is an Amiga group, but perhapse some of my 386 UNIX 
>experiance is worthwhile.  The 386/25 has a 64K external cache-- which is
>larger than the dhrystone program.  This test was ran under UNIX and MS-DOS.
>Under MS-DOS, it got 8000 dhrystones/sec which can be attributed to the 16
>bit regesters and added instructions that REAL 386 code can use. 

	Dhrystone is very susceptible to 64K+ caches, since it ALL gets sucked
into the cache.  Also, note that Dhrystone 1.1 is quite susceptible to
compilers "over"-optimizing it.  You should use dhyrstone 2.x to get
reasonable measurements (1.1 numbers can show a massive skew on some compilers/
machines, I thikn up to 50% faster than the "should").  See comp.benchmarks
for more info (and source code for 2.x).

>My machine (the 386/25) can accomodate 64K or 256K cache.  The version with
>256K was rated as best price/performance UNIX workstation by "Personal
>Workstation" for quite some time (until the 486's came along).  FYI, the 
>upgrade to 256K cache is $350.

	Once people start making them, cache should be easy to add (that 200
pin connector is made for it (and other things)).  Cache boards aren't really
complex, though testing them can be (and you have be very timing-concious).

>I think that C= could have made an external cache more accessable-- especally
>for the UNIX machine.  In that market, the extra $300-400 for a decent cache
>would not be missed...

	There's also the board space issue.  Look at an A3000 motherboard
sometime: it's quite packed.  It owuld have been very tough to fit it.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
The compiler runs
Like a swift-flowing river
I wait in silence.  (From "The Zen of Programming")  ;-)