Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.unix.amiga
Subject: Re: second thoughts on buying a 3000UX
Message-ID: <19512@cbmvax.commodore.com>
Date: 5 Mar 91 03:58:08 GMT
References: <61751@masscomp.westford.ccur.com> <1135@applix.com> <5PR9W6D@xds13.ferranti.com> <1145@applix.com> <13376@hubcap.clemson.edu>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 30

In article <13376@hubcap.clemson.edu> ddyer@hubcap.clemson.edu (Doug Dyer) writes:
>>If I spent all day just running X programs then the A3000 might make more
>>sense.  But, I spend all day compiling code.  I need max. disk and cpu
>>speed.  90% of the time graphics thruput contributes zip to my productivity.
>>The rest of the time, I'm maybe moving windows, which the 486 can do faster
>>on a 12MHz bus than the Amiga blitter on it's slow slow slow 7.14 MHz bus.
>
>The blitter isn't used under UNIX (see below).  The CPU is.  He he he

	Also note that most all existing VGA-etc boards have a LOT of wait-
states, so regardless of CPU/bus speed, you're card-limited.  The 3000 has
pretty efficient access to chip memory (with the 32-bit bus).  It does
need to sync to the slower bus, but I wouldn't be suprised if the bandwidth
available to the CPU (MB/s, gfx-mem to gfx-mem) was considerably higher on
the A3000 than on most or all VGA boards.  Plus you can run the blitter in
parallel with the CPU - even if it's slower at some things, overall throughput
is higher (and it is faster at non-nice conditions, I suspect).  Also you
get the the rest of the display hardware (copper, etc), which makes virtual
screens easy and very fast.

	Note: I haven't measured these things, I'm going on reports from IBM-
types about the number of wait-states to access video ram (I've heard numbers
as high as 12).

-- 
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")  ;-)