Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!attctc!chasm
From: chasm@attctc.DALLAS.TX.US (Charles Marslett)
Newsgroups: comp.sys.ibm.pc
Subject: Re: VGA cards: 8-bit vs. 16-bit
Summary: 16-bit modes are text and 256-color modes ONLY!
Message-ID: <8529@attctc.DALLAS.TX.US>
Date: 5 Jul 89 06:59:21 GMT
References: <3308@cs.dal.ca> <[267.1]comp.sys.ibm.pc;1@vpnet.UUCP>
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 28

In article <[267.1]comp.sys.ibm.pc;1@vpnet.UUCP>, kji@vpnet.UUCP (Ken Isacson) writes:
> The advantage of the 16 bit cards is that they are about twice as fast because
> the computer can get the video information to the card 16 bits at a time
> as oppose to 8 bits at a time.

Any VGA or EGA card running in the industry standard 16-color modes (as
opposed to the totally non-standard modes that ET3000 and C&T 441 based
cards can use -- that are really PC Jr. modes in disguise), WILL BE RUNNING
AS AN 8-BIT CARD.  16 bit cards are faster in the 256 color modes (almost
all of which will require 512K of RAM) and text modes (which are plenty fast
for most of us anyway).

There is a minor point I am ignoring here:  even in the 16-color modes,
the EGA/VGA interface can do 16-bit I/O instructions, so standard BIOS
access to the video memory (highly I/O intensive!) will be significantly
faster on a 16-bit card that supports 16-bit I/O instructions.  On the
other hand, efficient drivers for most screen intensive software will run
just about the same speed on an 8-bit card as on a 16-bit card.

> Hope this helps.

Ditto...

===========================================================================
Charles Marslett
STB Systems, Inc.  <== Apply all standard disclaimers
Wordmark Systems   <== No disclaimers required -- that's just me
chasm@killer.dallas.tx.us <== soon to be attctc.dallas.tx.us I think