Date: Mon, 23 Nov 1998 16:41:04 -0800 From: Darryl Okahata <darrylo@sr.hp.com> To: Sam Pigg <sam@redbacknetworks.com> Cc: chuckr@mat.net, freebsd-hardware@FreeBSD.ORG, smp@FreeBSD.ORG Subject: Re: tyan S1836DLUAN >512Mb problems Message-ID: <199811240041.QAA07352@mina.sr.hp.com> In-Reply-To: Your message of "Mon, 23 Nov 1998 09:21:34 PST." <199811231721.JAA14106@phred.redbacknetworks.com>
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Sam Pigg <sam@redbacknetworks.com> wrote:
> Sorry I didn't mention it, but I have swapped around the simms, and
> even got the vendor to provide a new set of 4 256 meg simms.
> Symptoms manifest themselves with any combination of simms larger than
> 512 Megs (though exactly 512 works fine).
[ You mean "DIMMs", not SIMMs". ]
Just another possible issue: with the old SIMMs, there was an
apparent cottage industry where people would take lots of older (lower-
density) memory chips and stuff them onto a board to make a SIMM. The
problem with these "lots o'chips" SIMMs was that they'd put a large
capacitive load onto the memory bus, with the result that you often
couldn't put more than one (pair) into a system. If you did, you ended
up with a system that either didn't boot, or crashed intermittently. If
you were "lucky", you could "fix" this by tweaking the BIOS to add main
memory wait states, but this wasn't particularly nice, as it slowed down
the system.
The result was that Pentium motherboard manufacturers added
comments to their manuals, which basically said not to use SIMMs with
more than "N" chips ("N" was something like 18-24 chips -- I don't know,
exactly).
Now, the question is whether or not there is a similar situation
with DIMMs (I don't know, as I'm still stuck in the Pentium I world).
If you have DIMMs with "lots o'chips", you might want to see if you can
find DIMMs with fewer memory chips. Yes, they'll probably cost much
more, but they might be more reliable.
--
Darryl Okahata
darrylo@sr.hp.com
DISCLAIMER: this message is the author's personal opinion and does not
constitute the support, opinion, or policy of Hewlett-Packard, or of the
little green men that have been following him all day.
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