From: jayson@tbag.UUCP (Jayson Phillips)
Newsgroups: comp.sys.amiga.hardware
Subject: re: Accelerate or not to Acceerate My Amiga 500
Date: 13 Apr 92 02:57:29 EST
Organization: Tampa Bay Amiga Group

>From: robtu@ico.isc.com (Rob Tulloh)
>Subject: Acclerate or not to accelerate my Amiga 500?
>Date: 10 Mar 92 23:41:39 GMT
>
>Hello,
>
>In the process of purchasing a new hard disk for my A500, I am tempted
>by the availability of accelerator boards such as the one from CSA which
>provide a 68030/40 chip which sits on the Amiga motherboard.
>
>My questions:
>
>1. If I don't have applications which directly say they work better
>   with an accelerator, will I notice any improvement in the performance
>   of my system? In other words, does adding an accelerator per force
>   improve my system speed or do programs have to know it is there?
 
All  applications  will  show  an  improvement in speed with an accelerator
whether  they  say it or not.  A 68030 accelerator will noticeably speed up
any  program  over  a stock 68000 Amiga.  A progam with an option to use an
FPU,  as in the 68881 or 68882, will show an even greater increase in speed
when  using  either  one  of  these and will use it if it is present.  Some
programs come in two versions.  One will require the presence on an FPU and
the  other  will  not.   Usually  the FPU version (also reqiring a 68020 or
68030)  will  run much faster than the non-FPU version when run on the same
020  or  030 system.  Usually the non-FPU version is ment to run on a stock
68000 Amiga but it may also run on an 020/030 system.
 
>2. There are many offerings of packages for the M-M Racer accelerator.
>   Some involve a 68030, 68040, math chip, and memory. Is it better to
>   invest in just a cpu? A cpu with the math chip? Add memory too?
>   There is a big difference between $400 for just a chip and a $1000
>   for a fast chip plus memory.
 
I'm  not  aware  of  the  M-M Racer coming in a 68040 version.  However, an
acclerator  with  a 25Mhz 68030 alone will generally speed up most programs
by  about  3  times over a stock 68000 Amiga.  If you add 32 bit configured
memory  to  this  you  will  generally see about an 8 times increase over a
stock  68000  Amiga.   Some programs will show a little less, others even a
little  more.   If  you  are  not  sure what you need then I would strongly
advise  you  to  get  the  CPU  and  at  least  2  to 4 megabytes of 32 bit
configured  memory.   This  will speed up most everything by about 8 times.
The  math chip  will only speed up the few programs that use it.  If you're
sure  that  you  are going to use a "math chip" program regularly and if it
comes  down  to money for either the FPU or the 32 bit memory, then you may
be  better  of  with  the  math  chip.  But if you're not sure, go with the
memory.  It'll speed up everything.
 
 
>Also, I have read that not providing fast (less than 50ns) ram to your
>accelerator will cause it to run as slowly as the 68000 chip. Is this
>necessarily true or based on how the accelerator is used?
 
I  used  to  run  a  68020 at 18MHz (LUCAS) in an Amiga 1000 with no 32 bit
memory  and  it  showed  an  average  increase  of  about 2.5 times on most
programs.  A friend has a GVP 25MHz 68030 accelerator with no 32 bit memory
in  his  Amiga  2000.   It shows about a 3 times increase in most programs.
Most  accelerators  take  80ns  or  60ns RAM and will not run any faster by
installing faster RAM.  The 68040 accerators for the A2000 use 80ns RAM and
generally  come  with  4MB  of  32  bit  RAM  already installed.  The 68040
accelerators  for the A3000 can come with or without 32 bit RAM as they can
access  the  32 bit RAM on the A3000 mother board.  The GVP G-Force 040 for
the  A3000  takes (expensive) 40ns RAM.  The PP&S Mercury 040 for the A3000
can  take  80ns, 60ns or 40ns RAM.  They claim it's faster with faster RAM.
No one has posted bench marks to "prove" this and it's not as obvious as it
might  seem.   The  speed difference between even 80ns and 40ns RAM on this
board  (and  others)  may  be  very slight due to the dual 4K caches in the
68040  CPU.   The  speed  difference may not be enough to warrent the extra
cost  of  the  expensive  high-speed  RAM.   For  instance, if the 40ns RAM
actually provided a 10% increase over the 80ns RAM (he said optimistically)
but  it  costs more than twice as much, then it is not worth it for me.  It
might  be  for you.  I'm  not aware of any 68040 accelerators available for
the A500, yet.
 
>Our news feed is gone so e-mail would be appreciated. I am hoping
>that this posting makes it out. Anybody else who is interested in
>feedback I get, let me know and I'll summarize what I receive and
>send it to you.
>
>Rob Tulloh (robtu@itx.isc.com or robertt@isc.com)
 
                            _        _   _   _   _
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  Tampa FL USA /--\ |  | | \_/ /--\  _) \_/ \_/ \_/ 6MB-RAM   Q105-HD
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