Conference hydra::amiga_v1

    A good place to do some research would be in the latest issue of the
    _AC Guide to the Amiga_, published by the Amazing Computing people. 
    Costs $12.95, I think, and should be available at almost any Amiga
    dealer.
    
    One of the biggest "wins" with an accelerator is the use of 32-bit wide
    RAM on the accelerator card.  Because it is twice as wide as memory
    available over the bus, and the processor is likely to be at least
    twice as fast as the 7.16 MHz 68000, right there you have a 4X speed
    advantage even without the other improvements of the 68020 and higher.
    IMHO, stay away from accelerators that do not offer this feature.
    
    Wes

I have that buyers guide, the summer issue.  It's a good starting point, but I'm
hoping to get more from people who have actual experience with some of this 
stuff.

For example, good point about the memory bus.  That would be one more plus for
the GVP all-in-one solution.


								John

re             <<< Note 5156.1 by KALI::PLOUFF "Devoted to his Lawn" >>>
>                           -< Some starting points >-


>    One of the biggest "wins" with an accelerator is the use of 32-bit wide
>    RAM on the accelerator card.  Because it is twice as wide as memory
>    available over the bus, and the processor is likely to be at least

	True, but....

>    twice as fast as the 7.16 MHz 68000, right there you have a 4X speed
>    advantage even without the other improvements of the 68020 and higher.

	Somehow I can't quite buy this,,,,,,

	It seems to assume that a stock 68000 is instruction or data 
fetch time bound and that if it gets twice as many bits at once it 
will somehow execute the instructions or apply the data twice as fast.
(may be true for some instruction sequences, I guess they're atypical)
To do this it would have to already be running at half its potential 
speed, if this is the case then someone at CBM screwed up pretty badly
a long time ago.  To get 4x the performance (without the effects of
caching) would require the processor to run at 4x the speed of a stock
68000, with memory serving up 4x as many bits per second (double the
width as well as halving the access time).  The 28MHz machines almost
get there, the 33MHz mahines are a little bit better than that. 

	Anyway, its still a tough decision, for the price of the kinds 
of upgrades being considered the power up programme may be most cost 
effective, assuming one can find a home for the existing 2000.

	Reg

    re .1 .3
    
    	We can work out timing of how this works, but the memory bandwidth
    is very important. A 33 MHZ accelerator NEEDS fast 32 bit memory. You
    lose over half the performance without it.
    
    	re .0
    
    	If you go with the GVP accelerator you lose the disk and memory
    when you disable the accelerator. I have not found this to be a
    problem. The only software that has trouble with the accelerator is
    games and they love running in a basic 1 MB  Amiga 2000.
    
    	As for the A3000 ... It has the same problem as a Amiga 2000
    with an accelerator but you can't disable the accelerator. So there
    are a number of games that you just can't run.
    
    		Steve P.
    

RE: .4

>    	If you go with the GVP accelerator you lose the disk and memory
>    when you disable the accelerator. I have not found this to be a
>    problem. The only software that has trouble with the accelerator is
>    games and they love running in a basic 1 MB  Amiga 2000.

Am I to take it from this that you have a GVP all-in-one accelerator/disk-drive
unit?  If so, how to you like it?  If you have a dot matrix printer, does it 
improve printing performance when you print bitmaps?  My system takes forever
to do this:  there are long pauses between each line printed when I do bitmap
in Pen Pal.  I'm assuming this will be at least as bad if not worse with Final
Copy.


								John

    BEWARE, some programs do not like fast processors!  When I print with
    DELUXE PRINT II, I must print with the 68000 (by reebooting) otherwise
    the printer could miss some escape codes and revert to text mode.  This
    is very intermittent, sometimes it occurs right at the beginning of the
    page and sometimes almost at the end.
    
    When I first added the accelerator, my Frame Grabber would not work at
    all, fortunately with version 2.0 of the software, they added a port
    delay parameter to slow down parallel port access so that the bits
    could have time to settle before they were sampled.
    
    Most games don't work with accelerators, but F18 is closer to real
    world (I think since I have never been in one), the plane rolls and
    dives and... MUCH faster.  Nice to have fallback to 68000 for stuff
    which will not tolerate 68030s.
    
    Jean
    

    Don't know if this helps your decision(s) but I am running an A2000,
    the old GVP accelerator (A3001) with 8meg 32bit memory, and a GVP HC8
    SCSI controller with 4meg onboard.  With this configuration my system
    runs whether or not I use the accelerator.  I can boot up with just the
    68000, disk(s), and 4meg memory by clicking on the 'boot68000' icon
    included with the GVP software.  When I do use the accelerator, which
    is all the time because I do not own many games, I have 8meg of 32 bit
    memory to run with, plus the 50mhz FPU.  The machine really cooks!  The
    Combo GVP board was not available when I bought my A3001 but I still
    like having the disk and some memory available, not matter what.  The
    drawback of this route is that I cannot use more than 9megs of
    memory(with the 1meg Agnus).  I do not know if the GVP combo will
    allow you to use your SCSI drives if the accelerator is disabled but I
    do believe that being able to access your SCSI drives without the
    accelerator is a MUST.(murphy's law, you know).
    Anyway, I think that by the time I will need more than 9meg of memory
    either the '040 boards will be readily available and debugged or a new
    more powerful machine will meet my needs.  There has been a bit of
    traffic on comp.sys.amiga.hardware on the GVP combo boards which may
    help.
    
    md
    
    

    	We can work out timing of how this works, but the memory bandwidth
    is very important. A 33 MHZ accelerator NEEDS fast 32 bit memory. You
    lose over half the performance without it.

Over half? I've got a set of benchmarks that show *much* worse than that.
Possibly you lose half if you've got full-speed 16-bit memory, but
7+ MHz 16-bit memory is worse than that; you typically have many wait
states after the request, and you may have a delay *before* the request
to synchronize the bus (that's the way it was explained to me, anyway).

I've got a number of timings on different cards with/without 32 bit
memory. The *best* of them are the Hurricane cards, which run in synch
with the bus, and hit 1.9 (best case test) times the speed of a stock Amiga. 
Most of the asynch cards were hitting 1.5 times the speed of a stock amiga 
on the same test.

This has been discussed elsewhere, but buying a 32-bit board without 32-bit
memory will help FP intensive things if you have an FPU, and not much else.

If you decide to stay with the 2000, I'd recommend an accellerator with 32
bit memory, and a hardcard. If you expect to run software that is both
memory hungry and broken so that it won't run on the 32-bit card, you might
get a SCSI controller with memory. But when you're running the 32-bit card,
you won't *want* to use the 16-bit FAST (the various memory sorters tend to
sort such to last on the allocation list anyway).

As for the 3000 - I went through that decision myself a while back. I found
that the cost of upgrading my 2000 was about the same as the cost difference
between a 3000 and what I could sell the 2000 for. I was willing to give
up games, though. The bottom line is that my 3000 will almost certainly be
worth more than a similarly equipped 2000 when I decide to upgrade again.

For raw CPU, the 2000 with a GVP will be faster. For graphics intensive
things, it's the other way around. Likewise, the disk will be faster than
anything except the "all-in-one" solutions. If you're going to buy an 040
card for the 3000, then the raw CPU numbers are liable to be the close to
the same.

When you consider the cost of the 3000, don't forget that you can buy a 500
tied to the TV for game use (which leaves your 3000 free when someone else
is suffering lemmingitis).

	<mike