Path: utzoo!news-server.csri.toronto.edu!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.unix.amiga
Subject: Re: second thoughts on buying a 3000UX
Message-ID: <19754@cbmvax.commodore.com>
Date: 11 Mar 91 21:11:53 GMT
References: <61751@masscomp.westford.ccur.com> <1135@applix.com> <5PR9W6D@xds13.ferranti.com> <1145@applix.com>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 37

In article <1145@applix.com> scotte@applix.UUCP (Scott Evernden) writes:
>In article <5PR9W6D@xds13.ferranti.com> peter@ficc.ferranti.com (Peter da Silva) writes:
>>In article <1135@applix.com> scotte@applix.UUCP (Scott Evernden) writes:
>>> In the end, I decided to brew myself a 486/33 box. 

>>If anything, X is the big reason to go with the 3000 rather than a [34]86
>>box.

>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 A3000 disk and CPU stuff all happens on the A3000's 25MHz, 32-bit wide 
bus.  Most '486s use relatively slow PIO driven hard disks.

When it comes to moving windows under X, blitter speed is probably not the
issue.  While the blitter does process at the equivalent of a 14.3MHz ISA
bus, the main point of X on an A3000UX would be that the CPU has a 32 bit
path to a 7.16MHz that runs with no wait states (at least in the monochrome
X that programmer's use).  Regardless of the video mode, the typical VGA card
takes 20-30 wait states per access, and if you stick to original VGA compatible
operations, you're stuck at 8 bits per access, whether on an ISA/AT or XT bus.

Of course, X on a PC vs. X on an Amiga is a fair test.  Windows on a PC vs.
Intuition on an Amiga is so skewed in the Amiga's favor, if you have any decent
comparative performance on the PC setup, you're extremely lucky, and you paid
for it.

>-scott


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
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	"What works for me might work for you"	-Jimmy Buffett