From owner-freebsd-questions@FreeBSD.ORG Mon Apr 27 14:30:48 2015 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id CFEE0804 for ; Mon, 27 Apr 2015 14:30:48 +0000 (UTC) Received: from cosmo.uchicago.edu (cosmo.uchicago.edu [128.135.52.97]) by mx1.freebsd.org (Postfix) with ESMTP id ACCE41BD6 for ; Mon, 27 Apr 2015 14:30:48 +0000 (UTC) Received: by cosmo.uchicago.edu (Postfix, from userid 48) id 7A72BCB8CA3; Mon, 27 Apr 2015 09:30:47 -0500 (CDT) Received: from 128.135.70.2 (SquirrelMail authenticated user valeri) by cosmo.uchicago.edu with HTTP; Mon, 27 Apr 2015 09:30:47 -0500 (CDT) Message-ID: <34690.128.135.70.2.1430145047.squirrel@cosmo.uchicago.edu> In-Reply-To: <553E401A.6119.163DF7C@g8kbvdave.googlemail.com> References: <553E401A.6119.163DF7C@g8kbvdave.googlemail.com> Date: Mon, 27 Apr 2015 09:30:47 -0500 (CDT) Subject: Re: Debugging bad memory problems From: "Valeri Galtsev" To: "Dave B" Cc: freebsd-questions@freebsd.org Reply-To: galtsev@kicp.uchicago.edu User-Agent: SquirrelMail/1.4.8-5.el5.centos.7 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Apr 2015 14:30:48 -0000 On Mon, April 27, 2015 8:56 am, Dave B wrote: > On 26 Apr 2015 at 23:05, Fernando Apesteguía wrote: > >> I booted from a memtest CD-ROM. It passed a couple of tests fine and >> then it rebooted while doing a "bit fade" test at around 93%. >> Removing the modules is tricky since this laptop has screws all >> around in dark corners (even removing the battery needs a screw >> driver). I will try to limit physical memory with hw.physmem and see >> if it makes any difference. >> >> Thanks! >> > > Check for CPU cooling problems too, such as an obstructed cooler or > grumbly > fan. (Also if you can, check for bad power supply issues.) > > Older AMD CPU's don't take kindly at all to running too hot, unlike some > Intel > devices that will start to cycle skipping to lower the disipation, just > slowing down > in effect. AMD might have been slightly behind Intel on this one: stepping down the clock (or diminishing clock multiplier to be more precise - "power now" they called the feature related to effectively changing the CPU speed). However, as far as I know, AMD chips were always more robust than Intel ones. You can boil water on it, and it still will keep running without glitches - as someone once put it. I do agree with your advice make sure the heat sink in not clogged: even though you will need more effort to heat AMD CPU to start on the chip memory controller failing compared to Intel CPU, still it well may be the snag. Valeri > > "Supliment the cooling" when running such tests, RAM can disipate quite a > bit of > power when worked hard (as Memtest86 does.) Elevate the laptop and waft > air > under it, but not in such a way as to oppose it's own intended airflow. > > Hope you find the trouble. > > Dave B. > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to > "freebsd-questions-unsubscribe@freebsd.org" > ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++