From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965444AbWFTDa4 (ORCPT ); Mon, 19 Jun 2006 23:30:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965449AbWFTDa4 (ORCPT ); Mon, 19 Jun 2006 23:30:56 -0400 Received: from meetpoint.leesburg-geeks.org ([66.63.28.250]:55820 "EHLO meetpoint.home") by vger.kernel.org with ESMTP id S965444AbWFTDaz (ORCPT ); Mon, 19 Jun 2006 23:30:55 -0400 Message-ID: <44976BED.4050600@leesburg-geeks.org> Date: Mon, 19 Jun 2006 23:30:53 -0400 From: Ken Ryan User-Agent: Mozilla Thunderbird 1.0.8 (X11/20060411) X-Accept-Language: en-us, en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: [RFC/SERIOUS] grilling troubled CPUs for fun and profit? Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > You accelerate nothing. Bit heaven? A CPU without a fan will go into > > a cold, cold, shutdown, requiring a hardware reset to get it out of > > that latched, no internal clock running, mode. > > Some CPU may do this, others will go via the random-generator mode > into the self-deformation-mode instead. A few years ago Tom's Hardware Guide made a cool video as part of an article on thermal emergencies. The article is here: http://www.tomshardware.com/2001/09/17/hot_spot/index.html The test was pulling off the CPU fan and heatsink while playing Quake. Granted it's not entirely realistic; I don't imagine the heatsink would come of during heavy gameplay (a more reasonable scenario THG mentions is the fan/heatsink coming off during shipping) however considering the preposterous little tabs AMD specs for their sockets I think sudden breakage is not out of the question. The video shows a PIII coping (halting), a P4 gracefully slowing down, and two variants of Athlon self-destructing (smoke and running solder). Evidently this set of tests convinced AMD to alter how they handled overtemp on their processors. The mobos in the test were built according to spec in terms of the thermal sensors and protection code in the BIOS. It didn't help; the exposed die of the Athlon ramped up its temperature way faster than the sensor could react. As for the ceramic package cracking, it is certainly possible, The ceramic is indeed designed for very high temperatures, but only if heated evenly. Give the package a 200C temperature differential within a second or two and thermal expansion is going to do some damage... I can certainly believe modern processors deal with sudden thermal rise better than the ones in the THG video. However not all of us can afford to always have the latest 'n' greatest... :-( ken