From owner-freebsd-questions@freebsd.org Wed May 20 18:02:56 2020 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4A5E42F068E for ; Wed, 20 May 2020 18:02:56 +0000 (UTC) (envelope-from galtsev@kicp.uchicago.edu) Received: from kicp.uchicago.edu (kicp.uchicago.edu [128.135.20.70]) by mx1.freebsd.org (Postfix) with ESMTP id 49S0wH3fLrz4XVq for ; Wed, 20 May 2020 18:02:55 +0000 (UTC) (envelope-from galtsev@kicp.uchicago.edu) Received: from [IPv6:2607:fb90:17c2:4dd:f846:ca97:b1ab:7638] (unknown [172.58.139.189]) (Authenticated sender: galtsev) by kicp.uchicago.edu (Postfix) with ESMTPSA id A5D084E65A; Wed, 20 May 2020 13:02:54 -0500 (CDT) Subject: Re: OT: Weird Hardware Problem To: Tim Daneliuk , freebsd-questions@freebsd.org References: <0a9f810d-7b4b-f4e6-4b7c-716044a9cf69@tundraware.com> <8b13e2f5-6ff4-ecc2-7036-c88cff0f5b6b@tundraware.com> <8732b894-0962-3546-4697-4c2ae0658cb8@kicp.uchicago.edu> <2a2afa7a-cbb9-4664-3b6b-4c955565e947@tundraware.com> From: Valeri Galtsev Message-ID: Date: Wed, 20 May 2020 13:02:53 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <2a2afa7a-cbb9-4664-3b6b-4c955565e947@tundraware.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 49S0wH3fLrz4XVq X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=uchicago.edu (policy=none); spf=none (mx1.freebsd.org: domain of galtsev@kicp.uchicago.edu has no SPF policy when checking 128.135.20.70) smtp.mailfrom=galtsev@kicp.uchicago.edu X-Spamd-Result: default: False [-1.53 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; DMARC_POLICY_SOFTFAIL(0.10)[uchicago.edu : No valid SPF, No valid DKIM,none]; NEURAL_HAM_MEDIUM(-0.26)[-0.264]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; NEURAL_HAM_LONG(-0.70)[-0.696]; MIME_GOOD(-0.10)[text/plain]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_HAM_SHORT(-0.67)[-0.666]; RCPT_COUNT_TWO(0.00)[2]; R_SPF_NA(0.00)[no SPF record]; RCVD_NO_TLS_LAST(0.10)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:160, ipnet:128.135.0.0/16, country:US]; RCVD_COUNT_TWO(0.00)[2]; MID_RHS_MATCH_FROM(0.00)[]; RECEIVED_SPAMHAUS_PBL(0.00)[172.58.139.189:received] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 May 2020 18:02:56 -0000 On 5/20/20 12:41 PM, Tim Daneliuk wrote: > On 5/20/20 11:07 AM, Valeri Galtsev wrote: >> Yes, it was I who mentioned electrolytic capacitors. > > Yeah, I am painfully aware of these issues, having started my career as > an analog circuit designer :) > > What made this one so weird is that the PS that isn't working on the Dell, > worked just fine on another machine that had _more_ drives in it and an > old power hungry AMD chip in it. > If you mean AMD CPU, then I can tell you that these CPUs opposed to Intel ones are awfully robust. You can literally boil water on AMD CPU, and it will keep running without glitches. I had once to have AC filters replaced in small server room VAC system which only could be done if all AC (air conditioning) is switched off. That took almost two hours during which main servers and number crunchers were left running. The temperature in the room was 96 F (36 C) - like on a beach in Honolulu. Few Intel based boxes got sick (not all if them but significant portion). None of AMD CPU based machines failed, they just kept running. Another factor: older CPUs have higher internal voltages. As you know, internal logics, like ALU, run at much lower voltages than those supplied to CPU. Though these are not directly related to external voltages on CPU pins, still... they quite likely will be more tolerant to higher voltage ripple in case of higher internal voltages. Valeri > -- ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++