[net.micro.amiga] Fraud And Deceit

rokicki@Navajo.UUCP (07/13/86)

In article <1391@amiga.amiga.UUCP>, jimm@amiga.UUCP (James D. Mackraz) writes:
> We have had reports that the drhystone benchmark runs significantly
> slower in extended memory than in a 512K machine, if that extended
> memory is CardCo.  Those with CardCo mem, can you check?  It would
> be interesting to measure differences in copying large files from
> RAM:a to RAM:b for a 512K machine vs. CardCo extended.

I've got one of those CardCo boards, and yes, it does slow the machine
down something awful.  Here are the stats:

	512K machine, 1.1		988 dhrystones
	1536K machine, 1.1		674 dhrystones
		Loss			 31.8%
	512K machine, 1.2 beta II	983 dhrystones
	1536K machine, 1.2 beta II	664 dhrystones
		Loss			 32.5%

Which means I just paid so many hundreds of dollars to SLOW DOWN MY
MACHINE!  Now, I've designed memory boards before; it's not that
difficult to make the RAM run with no wait states on a 7.2 MHz
machine.  To slow it down so much seems to indicate that two wait
states are being introduced for EVERY MEMORY REFERENCE!  This
is inexcusable.

(So is my use of capitals above, but I'm pissed.  I've been working
very hard squeezing every ounce of performance out of my programs, and
something like this comes out and destroys it all.)

rico@oscvax.UUCP (07/13/86)

In article <737@Navajo.ARPA> rokicki@Navajo.UUCP writes:
>
>I've got one of those CardCo boards, and yes, it does slow the machine
>down something awful.  Here are the stats:
>
>	512K machine, 1.1		988 dhrystones
>	1536K machine, 1.1		674 dhrystones
>		Loss			 31.8%
>	512K machine, 1.2 beta II	983 dhrystones
>	1536K machine, 1.2 beta II	664 dhrystones
>		Loss			 32.5%
>
>Which means I just paid so many hundreds of dollars to SLOW DOWN MY
>MACHINE!  Now, I've designed memory boards before; it's not that
>difficult to make the RAM run with no wait states on a 7.2 MHz
>machine.  To slow it down so much seems to indicate that two wait
>states are being introduced for EVERY MEMORY REFERENCE!  This
>is inexcusable.

FYI, I ran the same tests on my Amiga with a Comspec memory board and
the results were much more encouraging.  I only ran the tests once
each (OK so I'm lazy... gimme a break) so there is some variance
compared to the above figures on an unexpanded Amiga.  I used 50000
cycles with no registers on Manx Aztec C with 16 bit integers.  The
times were collected with my little brother's watch in stopwatch mode.
The numbers below have lots of digits after the decimal but I wouldn't
really trust them too much.  I've also included the actual time that I
measured for 50000 cycles.


    512K machine, 1.1		975.04 dhrys/sec = 51.28 secs for 50000 cycles
    2.5M machine, 1.1		967.49 dhrys/sec = 51.68 secs for 50000 cycles
    Comparison:  99.23% of top speed = 0.77% Loss

    512K machine, 1.2 Beta II	976.56 dhrys/sec = 51.20 secs for 50000 cycles
    2.5M machine, 1.2 Beta II	963.58 dhrys/sec = 51.89 secs for 50000 cycles
    Comparison:  98.67% of top speed = 1.33% Loss

As you can see, the times are close enough to each other that the stopwatch
method really isn't accurate enough to get a  good figure for the difference.
This should be good enough for the purpose of this experiment though.

Another FYI, the Comspec board uses 500mA in typical (not idle) operation.
Remember that's a 2 meg board...  I can't tell you too much about the
ground plane and such but it passes the "I can't see thru the PC board"
test.  Then again, maybe the light I was using wasn't bright enough :-)


DISCLAIMER: a) The Science Centre doesn't have anything to do with any of this.
	       Leave them alone!

	    b) I've enjoyed a healthy relationship with Comspec for a long
	       time now so my views may or may not be biased because of this.

	    c) I don't know what I'm talking about at the best of times :-)


	That's all
	  -Rico

		...{allegra|ihnp4|decvax|watmath|linus}!utzoo!oscvax!rico

perry@well.UUCP (07/15/86)

In article <737@Navajo.ARPA>, rokicki@Navajo.ARPA (Tomas Rokicki) writes:
> I've got one of those CardCo boards, and yes, it does slow the machine
> down something awful.  Here are the stats:
> 
> 	512K machine, 1.1		988 dhrystones
> 	1536K machine, 1.1		674 dhrystones
> 		Loss			 31.8%
> 	512K machine, 1.2 beta II	983 dhrystones
> 	1536K machine, 1.2 beta II	664 dhrystones
> 		Loss			 32.5%
> 
> Which means I just paid so many hundreds of dollars to SLOW DOWN MY
> MACHINE!  

Tomas,
	I am sorry that my original message warning against some memory
boards arrived too late to save you your pain but....for others out there:

	ASK BEFORE SPENDING! There are many other instances of otherwise
``reputable'' manufacturers making pure drek for the Amiga. Since when does
making a board for a C64 make you a genuis hardware designer? 

	I will have an Allegra in a few days and will report what I find.

Perry S. Kivolowitz

grr@cbmvax.UUCP (07/16/86)

In article <1435@well.UUCP> perry@well.UUCP (Perry S. Kivolowitz) writes:
>In article <737@Navajo.ARPA>, rokicki@Navajo.ARPA (Tomas Rokicki) writes:
>> I've got one of those CardCo boards, and yes, it does slow the machine
>> down something awful.  Here are the stats:
>
>Tomas,
>       I am sorry that my original message warning against some memory
>boards arrived too late to save you your pain but....for others out there:
>
>       ASK BEFORE SPENDING! There are many other instances of otherwise
>``reputable'' manufacturers making pure drek for the Amiga. Since when does
>making a board for a C64 make you a genuis hardware designer?
>
>       I will have an Allegra in a few days and will report what I find.
>
>Perry S. Kivolowitz

But Perry, why didn't you just post some facts, or ask for some other people
to discuss their experience with the different boards?

You initial posting sounded very much like one vendor was talking to you
about how lousy their competitors products were.  And then you seemed to
be repeating this as vague warnings and some technically questionable
assertions, without your really understanding all the issues involved.

Sorry, but your initial posting was most irritating...
--
George Robbins - now working with,      uucp: {ihnp4|seismo|caip}!cbmvax!grr
but no way officially representing      arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department       fone: 215-431-9255 (only by moonlite)