Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!ucsd!ames!lll-winken!uunet!jarthur!cdouty
From: cdouty@jarthur.Claremont.EDU (Christopher Douty)
Newsgroups: comp.graphics
Subject: Re: What is more important????
Message-ID: <571@jarthur.Claremont.EDU>
Date: 26 Mar 89 03:09:49 GMT
References: <1663@aucs.UUCP>
Reply-To: cdouty@jarthur.UUCP (Christopher Douty)
Distribution: na
Organization: Harvey Mudd College, Claremont, CA
Lines: 45

In article <1663@aucs.UUCP> 870646c@aucs.UUCP (The Buck Stops Here!) writes:
>In trying to determine the best route in which to upgrade my Amiga 2000 to 
>reduce the time needed to do ray tracing, I need to know if it would be 
>more important to obtain an upgrade board with the following:
>
>68020 running at the normal 7.14Mhz clock speed, with a 68881 running at 
>16Mhz(full 32 bit path used), the reduced speed on the 68020 ensures 
                                                        ^^^^^
>compatability with all software. Expected speed increase for normal prgs. is
>62%(ones that do not use the math chip). Price $500.00 US(includes the 68020
>and 68881).
>
>My big question is this: "Under normal ray tracing, would the prg. make more
>use of the 68881 or the 68020(which is more important)? Of course the program
>itself only uses the 68020, but how much math is really being done???

>Barry Comer   870646c@aucs.UUCP


First off, the speed of the 68020 has no bearing on compatability.  If the
program was poorly written so that it will GURU a '020 machine, it will
bring the walls tumblin' down no matter what the clock speed.

Apparently in programs which were not specifically compiled with in-lin FPU
code the speed of the CPU (68020) makes a bigger difference than the FPU.
Normal Sculpt-3d (not the '881 version) renderings are about twice to four
times as fast with a 16Mhz 68020.  

To really make a difference in your ray-trace times, you should get both the
CPU and FPU going as quick as you can and use programs compiled specifically
for that pair.  You might want to check out the A2620 board from Commodore.
It will plug right into your 2000 with no fuss, and it includes 2 megs
32-bit RAM for about the same price as a RAM-less CSA or Ronin board.
Another possible choice would be Great Valley Products new '030 board.  It
probably costs a mint but is disgustingly fast, has 32-bit RAM, AND a
built-in SCSI controller in addition to a 25MHz (?) 68030/68882 combo.

I hope that this random rambling helps.  I know that a 68020 makes
everything on the machine much snappier and can vouch for the A2620.

Christopher Douty
cdouty@jarthur.claremont.edu

with STANDARD_DISCLAIMER;  use STANDARD_DISCLAIMER;
with SILLY_QUOTE;  use SILLY_QUOTE;