From owner-freebsd-hardware Wed Aug 22 3:10:25 2001 Delivered-To: freebsd-hardware@freebsd.org Received: from borja.sarenet.es (borja.sarenet.es [192.148.167.77]) by hub.freebsd.org (Postfix) with ESMTP id D243C37B40B for ; Wed, 22 Aug 2001 03:10:16 -0700 (PDT) (envelope-from borjam@sarenet.es) Received: from there (localhost [127.0.0.1]) by borja.sarenet.es (8.11.3/8.11.3) with SMTP id f7MA98V17043; Wed, 22 Aug 2001 12:09:09 +0200 (CEST) (envelope-from borjam@sarenet.es) Message-Id: <200108221009.f7MA98V17043@borja.sarenet.es> Content-Type: text/plain; charset="iso-8859-1" From: Borja Marcos Organization: Sarenet S.A. To: "Brian" Subject: Re: 3ware stuff not ready for heavy duty useage-followup Date: Wed, 22 Aug 2001 12:09:08 +0200 X-Mailer: KMail [version 1.3] References: <03d801c12a9e$bab359c0$6601a8c0@elitists.org> <005101c12aa5$7dd36160$0201a8c0@fear.wrath.net> In-Reply-To: <005101c12aa5$7dd36160$0201a8c0@fear.wrath.net> Cc: freebsd-hardware@freebsd.org MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Wednesday 22 August 2001 02:58, you wrote: > I admit to being a dumb college kid. > > OK, the most energy I've ever seen a drive take is when it's powering u= p > (common sense). I can't remember seeing a drive that required more tha= n 3 > amps to power up. 12v x 3a =3D 36 watts. A general rule of thumb is t= hat > the read/write power is half of that that takes to spin the disk up. S= o > let's see, that would be 18 watts. > > 8 disks x 36 watts/disk ~ =3D 290 watts. So, she should be definitely = safe > with a 400 watt power supply. It should very much definitely handle it > when running. > > Now, I've got a crappy 235watt power supply. It handles my six drives,= my > dual katmai p3-550's, a pair of dual fan cpu fans, and three fans. Sur= e, > you can attempt to ridicule me for doing such things, but I shall ridic= ule > you for being impractical. =09It is not only a matter of watts. A 300 W PC power supply *cannot* giv= e 25 A=20 at 12 V. Such supplies use to have limitations. You can get 300 W adding = the=20 currents it can supply for +5 V, -5 V, +12 V and -12 V. =09Borja. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message