Path: utzoo!utgpu!watmath!att!dptg!rutgers!tut.cis.ohio-state.edu!purdue!bu-cs!madd
From: madd@bu-cs.BU.EDU (Jim Frost)
Newsgroups: comp.sys.ibm.pc
Subject: Re: 80386 memory expansion board needed
Message-ID: <36052@bu-cs.BU.EDU>
Date: 8 Aug 89 04:22:57 GMT
References: <35950@bu-cs.BU.EDU> <1151@mitisft.Convergent.COM>
Reply-To: madd@bu-it.bu.edu (Jim Frost)
Followup-To: comp.sys.ibm.pc
Organization: Boston University Distributed Systems Group
Lines: 23

In article <1151@mitisft.Convergent.COM> burton@mitisft.convergent.COM writes:
|In article <35950@bu-cs.BU.EDU> madd@bu-it.bu.edu (Jim Frost) writes:
|>I have a Northgate 386-16 machine with 4Mb of memory, which is
|.
|. (deleted)
|.
|which had myriads of AT expansion boards but I'm not too keen on
|.
|.
|A somewhat related question is whether or not you can take 16 bit memory boards,
|say an AST ADVantage, with 120/150 ns memory, and run it successfully on a
|20 or 25 MHz system.  Is this possible?  How much does performance suffer?
|Does a RAM cache on the motherboard help any?

Yes, it can be done, but most 386 machines run the I/O bus at 8MHz
while the 32-bit memory bus runs at CPU speed -- typically 16MHz,
20Mhz, 25MHz, or 33MHz.  Even at the slowest speed you're talking
about at least half of the performance.  A cache will help, often
quite a bit, but it's still not going to be the same as 32-bit memory.

jim frost
software tool & die
madd@std.com