Path: utzoo!utgpu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!ists!yunexus!xrtll!silver
From: silver@xrtll.uucp (Hi Ho Silver)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Upgrading 256K VGA to 512K VGA card
Message-ID: <1990Dec25.172332.14826@xrtll.uucp>
Date: 25 Dec 90 17:23:32 GMT
References: <7900@hub.ucsb.edu> <62M^M8#@rpi.edu>
Reply-To: silver@xrtll.UUCP (Hi Ho Silver)
Distribution: comp
Organization: Not around here, pal!
Lines: 29

In article <62M^M8#@rpi.edu> sunyat@itsgw.rpi.edu (Eric Hsiao) writes:
$Hi, I got a 16 bit VGA card that currently has only 256K on it.  I want to
$upgrade it to 512K so I can display 640x480x256, 800x600x256, 1024x768x16, etc.
$The manual says I need 256Kx4 Fast Page Mode Dram (sometimes called 1-Mbit
$DRAM).  Anyone know where I can get these chips at a reasonable price ($15-$20)?

   Are you sure your manual is correct?  If it's a 16-bit card using 256Kx4
chips, the minimum amount of memory on it would be 512K (because you'd need
four chips to make it 16 bits wide, and that would be 256Kx16 bits = 512K).
I haven't seen a VGA card that uses 256Kx4 chips (though that certainly
doesn't mean there aren't any).  Have a look at your board and count the
number of RAM chips on it.

   The other alternative is that it doesn't use 256Kx4 chips for 256K, and
then you'd end up eating the chips currently on it ...

$Does it matter whether I get 80ns or 100ns?  Will it increase the speed of
$the display card?
 
   It probably doesn't matter, and getting fast RAM won't speed up your board
because it's built to assume a certain clock speed; anything faster is
wasted.  Look at the numbers on your RAM chips.  If they end in -10, they're
100 ns.  In any case, if the manual doesn't say what the slowest acceptable
chips are, then buy the same speed as the chips on your board.
-- 
 __            __  _  | ...!nexus.yorku.edu!xrtll!silver |  always
(__  | | |  | |_  |_) >----------------------------------< searching
 __) | |_ \/  |__ | \ | if you don't like my posts, type |    for
_____________________/  find / -print|xargs cat|compress |   SNTF