[comp.sys.mac.hardware] Slowness of 8*24GC card

housen@ssc-vax (Kevin Housen) (11/28/90)

We recently installed an 8*24GC video card on an FX.  The spec sheets
imply that the card should speed up some graphics operations by a
factor of 5 to 30.  We have found that the card does speed up some
things.  However we have also found that the card actually degrades
performance in other cases.  I am wondering if anyone else has played
with the card and has had similar experiences.

An article in the Nov 13 MacWeek summarized some speed tests with
and without the GC card.  E.g. they found significant speed increases when
scrolling through a MS Word document.  We found comparable results in 
Word (factor of 1.3 speed increase in 1 bit mode, factor of 4 in 24 bit
mode).  However, when scrolling the same document in WriteNow 2.2,
we found that scrolling with the GC turned on was a factor of 3
slower than it was with the card off (that test was in 1 bit mode).
So Word and WriteNow showed opposite trends.

I wrote a quick ditty that does repeated CopyBits calls, drawing an
image at random locations on the screen.  We found that (in 8 bit mode)
the progam ran a factor of 2 slower when the GC was turned on
compared to when it was off.

I wrote another program which draws 16000 random lines on the
screen.  In that case, the card sped up the drawing by a factor of 2.

Does anyone have any idea whats going on here?  Right now I am of
the opinion that before buying one of these cards, you ought to test
it with the software you plan to use.

BTW, the tests mentioned above were done on an FX with 8 Meg,
an Apple Two Page monitor, System 6.05, no INITs (other than
the GC INIT).  The GC card has the extra DRAM installed.  I also
tested the card on a vanilla Mac II, with similar results.

Thanks heaps -

Kevin Housen
housen@ssc-vax

J.COOK@ENS.Prime.COM (12/04/90)

Kevin Housen at <housen@ssc-vax> writes about "Slowness of 8*24GC card":

>We recently installed an 8*24GC video card on an FX.  The spec sheets
>imply that the card should speed up some graphics operations by a
>factor of 5 to 30.  We have found that the card does speed up some
>things.  However we have also found that the card actually degrades
>performance in other cases.  I am wondering if anyone else has played
>with the card and has had similar experiences.
...

Pick up a copy of the latest Macworld - the one with John Scully on the
cover in a Samuri outfit.  It compares the performance of a number of
accelerator graphics boards including the 8*24GC to each other and to
an unaccelerated IIfx.  One important thing they do is to vary the tests.
i.e. don't draw all long lines or fill only large regions - test drawing
many small lines or filling many small regions.  One of the things they
bring out is that sometimes getting the accelerator card to do the operation
exceeds just "doing it yourself" (having the 680x0 do it) because of the
additional setup involved to hand the operation off to the accelerator card.

There may be other possibilities, but you didn't mention your comparison
methods and list the operations in detail.

Jim Cook
<j.cook@ens.prime.com>
"Just my opinions.  Prime has its own."

J.COOK@ENS.Prime.COM (12/04/90)

Correction to my previous note, where I wrote:

>There may be other possibilities, but you didn't mention your comparison
>methods and list the operations in detail.

Actually, you did list your methods and operations in detail.  Duuuuh.

Okay, the other possibilities:

1. WriteNow may have its own custom routines.  The previously cited MacWorld
   article mentioned this with a couple other major utilities (Pagemaker was
   one, I think).  Obviously, it isn't going to be accelerated.

2. Copybits acceleration is affected by (a) quad-16bit-word alignment of
   the port - see TechNote 277 and (b) whether you use the new GWorld calls.

Other ideas?
Phase of moon, relation of planets, cosmic rays, ...

rlong@phonon.eng.ohio-state.edu (Prof. Ronald Long) (12/05/90)

Has anyone tried the 8*24GC card with SoftPC-EGA/AT?

I have wondered if it would provide a performance boost.




-- 
Ronald K. Long
Ohio State Univ EE Dept., 2015 Neil Ave., Columbus, OH 43210
rlong@phonon.eng.ohio-state.edu

pfile@sprite.berkeley.edu (Rob Pfile) (12/05/90)

In article <6286@quanta.eng.ohio-state.edu> rlong@phonon.eng.ohio-state.edu (Prof. Ronald Long) writes:
>Has anyone tried the 8*24GC card with SoftPC-EGA/AT?
>
>I have wondered if it would provide a performance boost.
>
Well, I have the old 2-card AST Mac286 board set, and at least with
this (somewhat old) hardware and v2.0 of AST's software, the 8*24GC board
shuts it's accelerator down... So much for Flight Simulator!

>-- 
>Ronald K. Long
>Ohio State Univ EE Dept., 2015 Neil Ave., Columbus, OH 43210
>rlong@phonon.eng.ohio-state.edu

Rob Pfile
pfile@sprite.berkeley.edu

sands@apple.com (Michael Sands) (12/06/90)

There are some (?) applications that do not adhere to the Macintosh 
programming guidelines.  They achieve acceleration by doing things behind 
QuickDraw's back.  Many of these same applications break or actually go 
slower when running with the GC card.

Apple tested many applications with the GC card.  The companies with 
applications that did not work were informed and many promised to release 
revised working versions.  The list of incompatible applications is 
available from the dealers.

Michael Sands
system extension group
(408) 974-6108
novice driver, just my thoughts

bell@pyro.ei.dupont.com (Mike Bell) (12/06/90)

In article <11434@goofy.Apple.COM> sands@apple.com (Michael Sands) writes:
>There are some (?) applications that do not adhere to the Macintosh 
>programming guidelines.  They achieve acceleration by doing things behind 
>QuickDraw's back.  Many of these same applications break or actually go 
>slower when running with the GC card.
>
>Apple tested many applications with the GC card.  The companies with 
>applications that did not work were informed and many promised to release 
>revised working versions.  The list of incompatible applications is 
>available from the dealers.
>
>Michael Sands
>system extension group
>(408) 974-6108
>novice driver, just my thoughts



   Unfortunately, MacX (the one from Apple) is one of those programs that
has problems with the 24GC card.  When you try to display a program that 
does color animation (a color ico, for example), all that get is a black,
flickering window.  I was particularly bummed by this, because I was really
hoping that the GC card would make MacX fly.......







				Mike




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Mike Bell                                Internet: bell@opus.wizards.dupont.com
Senior Engineer                          CSNet: BELLMA%ESVAX@dupont.com
DuPont CR&D  				 Applelink: D2747
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