Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!rutgers!att!cbnewsm!nsw
From: nsw@cbnewsm.ATT.COM (Neil Weinstock)
Newsgroups: comp.sys.amiga.tech
Subject: Chip memory bandwidth, graphics modes
Message-ID: <8219@cbnewsm.ATT.COM>
Date: 3 Jan 90 17:54:52 GMT
Reply-To: nsw@cbnewsm.ATT.COM (Neil Weinstock)
Organization: The Flying Squid Patrol
Lines: 20


Oh well, another decade, another few grey cells gone.  While reading the
description of the Black Belt graphics enhancer (provides 8-bitplane graphics
modes in a fairly funky way), I remembered a question that I have had for a 
while, but it usually slips away before I ask someone.

Why can the Amiga handle 4 bitplanes at 640 pixels/line, but only 6
bitplanes at 320 pixels/line?  I understand limitations on number of color
registers and the like, but that shouldn't have any bearing on the potential
for future enhanced chipsets to handle 8 bitplane modes.  Nonetheless, we
hear periodically that the Amiga just *can't* handle more bitplanes/colors
due primarily to chip memory bandwidth limitations.

I can't seem to make this all add up.  Can someone clarify?

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