Date: Sat, 22 Jul 2000 17:18:03 -0500 From: "Jeffrey J. Mountin" <jeff-ml@mountin.net> To: "Rodney W. Grimes" <freebsd@gndrsh.dnsmgr.net> Cc: lioux@uol.com.br (Mario Sergio Fujikawa Ferreira), freebsd-stable@FreeBSD.ORG Subject: Re: Signal 11 on 4-Stable buildworld; bad memory or what? Message-ID: <4.3.2.20000722162331.00d5ec70@207.227.119.2> In-Reply-To: <200007211953.MAA39777@gndrsh.dnsmgr.net> References: <4.3.2.20000721132938.00b49400@207.227.119.2>
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At 12:53 PM 7/21/00 -0700, Rodney W. Grimes wrote: >Note also that OC'ing can cause _permanent_ damage to semiconductors, >and that clocking down to spec may still leave you with hardware that >does not function correctly. The predominant failure mode is caused >by something called electromigration that has to do with metal migrating >into the semiconductor due to operating at excessive temperature. Certainly, but excellent cooling is a must when OC'ing, even if one is just doing a quick test to see if the CPU can be OC'ed. Electromigration can happen when running a CPU within specs, except for sufficient cooling. >Electromigration is a non reversable process, and it only takes a few >microseconds to occur should the temperature at a metal/silicon interface >rise above a certain threshold, this spot heating occurs on the microscopic >level and external temperature monitoring has very little, if any, >visibility into it. This problem becomes more and more critical as >geometries shrink. A design flaw can also attribute. My C instructor ran into to this years back with an Alpha when using 2 registers in a tight loop. The layout had them adjacent on the chip, resulting in excessive heat explaining the odd failures. Didn't care to add more to OC'ing, but what the hey. Just run for cover afterwards. ;) OC'ing non-Intel processors has shown the smallest gain. As mentioned on the list they already run hot. Trying to squeeze more out is asking for trouble. A good OC'ing text *should* mention this. While I no longer have any OC'ed servers, I do make sure to have better processor cooling and prefer 2 fans per CPU. Should one fail, the cooling is sufficient, since most are designed for OC'ing. http://www.computernerd.com/ I've used products from the first for some time now. The FC-PGA pages are buried at: http://www.computernerd.com/futu33.html Those that like to OC may wish to check out: http://www.computernerd.com/futu36-1.html For links to various cooling suppliers check out: http://www.heatsink-guide.com/ Jeff Mountin - jeff@mountin.net Systems/Network Administrator FreeBSD - the power to serve To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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