From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: A4000(Speed) -=> FALCON (Speed)
Date: 11 Dec 92 12:20:31 GMT
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA

In article <1992Nov24.153452.880@gserv1.dl.ac.uk> g.coulter@daresbury.ac.uk writes:
>Hi Everyone, I hope that one of you can put me straight on this:

>I am trying to find out just how much faster the A4000 will be 
>the Falcon. I have heard that the Falcon is about 6 times faster
>than the A500 

Don't count on it for most things.  The Falcon runs a 16MHz 68030 on a 
16-bit bus.  Assuming this memory is reasonably fast w.r.t. this '030,
you could average maybe 2x-2.5x the overall integer performance of the 
A500.  Actually, a 68030 on a 16-bit bus with caches off is slower on
the overall than a 68000 on the same 16-bit bus.  The numbers I pulled
out here assume a faster memory bus for the 68030 in the Falcon (a slower
wide bus, as in the A1200, would give you the same boost).  

If you're comparing floating point math, a Falcon with an FPU would be
considerably faster than the A500, maybe 5x-10x depending on the job.

>and that the A4000 is about 39 times faster. 

I don't know where that number came from.  The A3000 is roughly 8x faster
than an A500/A1000/A2000 in integer math, but again that's very application
dependent.  A chip-bound operation may only be twice as fast, some very
cachable code could be even faster.  The 25MHz clock, fast 32-bit burst 
memory bus, and cache contribute to this speed.  How do you want to make
up the numbers?  The best way is to run some kind of benchmark on each
machine.  I can tell you than A3000 Fast memory is 5.6x faster non-burst, 
10.2x faster burst, than that of the 68000-based Amigas.  The clock is 3.6x
faster.  But all of these factors apply to the A4000, yet we mark the 
A4000 as roughly 3x faster than the A3000, even though it uses the same
basic system design.  That's due to the much more efficient 68040 design and
larger cache.  

>Also if a 68882 is added to the Falcon, how much of an overall
>speed improvement is gained?

It depends.  If you're running code that uses floating point math, it may
give you a 5x-10x boost on math, though I'm not sure what kind of penalty
an FPU on a 16-bit bus takes, we've never run one.  Most kinds of code
don't get any improvement.  Even code that's FPU intensive can be 70% or
more actual integer operations.

>I am not trying to start a war here but does anyone know of any
>rumors regarding a possible DSP sound processor for the Amiga.

There will be DSP on the Amiga in the future.  It will handle sound, but
it won't be restricted to sound (eg, it won't use the Motorola DSP 56001).
The 56001 is a 24-bit fixed-point DSP.  That's enough to go from the 
threshold of human hearing to a bit beyond the threshold of pain, but it's
no use for most graphics processing or other scientific applications.

-- 
Dave Haynie / Commodore Technology, High-End Amiga Systems Design (cool stuff)
 "The Crew That Never Rests"  {uunet|pyramid|rutgers}!cbmvax!daveh   BIX: hazy
		SCIENCE:	"I'll believe it when I see it"  
		RELIGION:	"I'll see it when I believe it"

Newsgroups: comp.sys.amiga.hardware