Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!ico!vail!scottw
From: scottw@ico.ISC.COM (Scott Wiesner)
Newsgroups: comp.unix.i386
Subject: Re: How to choose a new 386 UNIX PC...
Message-ID: <16081@vail.ICO.ISC.COM>
Date: 13 Sep 89 19:52:24 GMT
References: <641@visdc.UUCP>
Organization: Interactive Systems Corp, Boulder, CO
Lines: 39

From article <641@visdc.UUCP>, by jiii@visdc.UUCP (John E Van Deusen III):
> In the June 1989 issue of BYTE Magazine, Bradley Dyck Kliewer wrote an
> article entitled "Debunking 16-bit VGA.  In that article he tested six
> 16-bit VGA adaptors for the AT bus.  He states that of all the boards
> tested, none had 16-bit latch registers.  His benchmark tests for
> copying a block of pixels to the entire screen byte by byte gave results
> in the 10 to 20 second range (for video mode 16, which I assume is
> 1024x768x16 colors?).  I am not convinced that level of performance
> would cut it for an X-terminal application.  Mr. Kliewer suggests using
> graphics coprocessor boards; are cheaper ones coming?

8 bit vs. 16 bit really nets you nothing for most graphics operations
on a VGA board.  This is mostly marketing hype.  They're getting faster
text mode operation (where you write an attribute and data byte pair), 
but the EGA and VGA are 8 bit devices internally.  Everything you do
to one of these adapters goes through an 8 bit data path internal to the
card, and for most operations, you must do 8 bit memory access to the
card for things to work right.  

The only advantage to some 16 bit boards is that they're often from a
newer generation of VGA chips, which makes them faster.  The companies
could just as easily make an 8 bit card from these newer chips, but 
the market demands 16 bit cards these days.  

In my work, I see a fairly wide range of performance in different VGA
cards.  It's a situation where you get what you pay for.  The TSENG Labs
based cards (Orchid, Genoa, STB, etc.) are a very good value.  1024x768
with 16 colors is nice.  The performance isn't as good as more expensive
cards such as those made by Video 7, but for most things, it's still
acceptable.  There are new boards just around the corner coming from many
vendors that will have better performance for lower cost.  It's an ever-
evolving market.

On the subject of graphics coprocessor boards, the IBM 8514/A looks very
good, and when the AT clones of this board become available later in the
year, there will be a lot of happy people.

Scott Wiesner
Interactive Systems