Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!uakari.primate.wisc.edu!uflorida!ufqtp!sutherla
From: sutherla@qtp.ufl.edu (scott sutherland)
Newsgroups: comp.sys.amiga.hardware
Subject: One more Amiga RAM question. ;*)
Message-ID: <928@orange9.qtp.ufl.edu>
Date: 27 Feb 90 15:46:31 GMT
Reply-To: sutherla@qtp.ufl.edu (scott sutherland)
Distribution: na
Organization: University of Florida Quantum Theory Project
Lines: 43



	Well, I have asked several questions about memory expansion and
the Amiga, specifically w.r.t. the A2091 and A2630.  Now I am more 
informed AND more confused.  What I have been told is that, for the
A2091, I need 16 256K x 4 CMOS DRAM 120 ns chips for 2 Megs.  I can find
these in Computer Shopper for ~8 ea.  Now, for the A2630, I have been
told that I need, get this, 256K x 4 CMOS DRAM 100 ns chips (or faster).
NOW I AM REALLY CONFUSED.  

	How can the A2091, which uses 16-bit RAM, and the A2630, which
uses 32-bit RAM, use the same type of chips, with the only difference
being the SPEED??????????  If this is true, do I use the same number
of the faster chips for 2 Megs on the A2630?? 

	The specs on the A2630 state that it comes with 2 Megs of 
100 ns RAM.  According to the Amiga World review (March 1990), they
should have used 80 ns or 70 ns RAM, like the Hurricane and other
'030 boards.  AW also says that the 2 Megs on the A2630 are soldered
in and would be difficult to remove.  My question is this.  If I leave
the 2 Megs of 100 ns RAM in there and decide to add two more Megs of
32-bit RAM, DO I HAVE TO USE 100 ns RAM, OR CAN I USE 70 OR 80 ns RAM
TO IMPROVE PERFORMANCE????   What will be the effect, if any, (especially
adverse effects) of having 2 different speeds of RAM on the board?  Would
I be better off removing the original 2 Megs and using the same chips for
all 4 Megs?

	A couple of extra questions.  I have been told that I MUST use CMOS
chips and not NMOS chips.  None of the places in the Computer Shopper
specify whether the chips they list are CMOS or NMOS.  How do I differentiate?
And finally, Dave Haynie told me that the chips for the A2630 were NOT only 
256K x 4 CMOS DRAM 100 ns chips, BUT that they must be in the ZIP package.

What in the world is a ZIP package???  Again, none of the advertisers in CS 
mention anything about ZIP!!  They mentions SIMMS, but NO ZIPS.  Why do I need
ZIP?  How do I determine if a chip advertised in CS is ZIP or not???

	AS YOU CAN SEE, I AM TOTALLY CONFUSED.  ANY HELP IN "STRAIGHTENING
ME OUT" WOULD BE APPRECIATED.

Thanks,

Scott Sutherland
sutherla@qtp.ufl.edu