Newsgroups: comp.sys.amiga.hardware
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!metahawk
From: metahawk@itsgw.rpi.edu (Wayne G Rigby)
Subject: Re: Question about the difference between A3000-16/50 and A3000-25/50
Message-ID: <gj5g2jc@rpi.edu>
Keywords: A3000 speed
Sender: Wayne Rigby
Nntp-Posting-Host: jec414.its.rpi.edu
Organization: Rensselaer Polytechnic Institute, Troy NY
References: <116684@tut.cis.ohio-state.edu>
Date: 5 May 91 07:12:04 GMT
Lines: 43

In article <116684@tut.cis.ohio-state.edu> erd@giza.cis.ohio-state.edu (Ethan R Dicks) writes:
>I am considering upgrading from an A1000 to an A3000.  I would like to stay
>cheap and get an A3000-16/50 through the "Power Up" program.  I intend to
>add an '040 board, when they are available, but I am concerned about the
>bus speed.  Is the 68040 co-processor slot synchronized with the motherboard
>clock?  I realize that the CHIP RAM operates at a 14.xx Mhz to be NTSC
>compatible and that the processor is asynchronous with respect to it, but
>what about a co-processor?  I know that the co-processor on the A2000 is
>synchronized when accessing motherboard/Zorro II RAM but it has local 32 bit
>memory.
>
>In short: if I buy a 3000-16/50, will any future '040 run at a higher speed?
>If I intend to run a 25 Mhz '040, will I need an A3000-25/50?  I am aware of
>RAM speeds and can select any FAST RAM to be of the appropriate speed for
>either 16 or 25 Mhz.
>
If you got an '040 board, the board would basically take over the bus and
run at its own clock speed.  So if you got, for example, a 70 MHz 68070
accelerator board, your computer would run at 70 MHz, and your 16 MHz
68030/68881 or 25 MHz 68030/68882 would be disabled for all intents and
purposes.  Of course, if you had a coprocessor board that ran at the same
speed as your on board CPU, it would be possible to use both of the processors
(the '040 & '030/882).  This, of course, will not be seen for a while, since
the present OS doesn't support dual processors; but as some future development,
it might be seen. 

>Thanks,
>-ethan
>
>
>
>
>--
>Ethan R. Dicks       | ######  This signifies that the poster is a member in
>Software Results Corp|   ##    good sitting of Inertia House: Bodies at rest.
>940 Freeway Drive N. |   ##
>Columbus OH    43229 | ######  "You get it, you're closer."

                                   Wayne Rigby
                                   Computer and Systems Engineer (in training)
                                   Rensselaer Polytechnic Institute
                                   metahawk@rpi.edu