Marginal OEM Power Supply
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From: Bill Davidsen on 27 Jun 2010 20:54 Robert Myers wrote: > Bill Davidsen wrote: >> Robert Myers wrote: > >>> It's misleading for me to say that the CPU has no fan. The case fan >>> draws air in such a way that the predominant flow is through the many >>> horizontally stacked, spaced plates of the heat sink. It wouldn't >>> seem that it would matter so much where the air comes from, but >>> apparently it does. The heat sink stack is so tall it extends nearly >>> to the edge of the case, so that air entering through the side holes >>> (highly turbulent because it is a collection of small jets) >>> encounters the top of the heat sink almost immediately. I suspect >>> that those holes behave more like vorticity generators than like a >>> duct. Take the cover off, and the relatively laminar flow through >>> the heat sink doesn't create enough heat transfer. >>> >> Possible, but I think having the coolest outside air coming to the CPU >> first is probably the key. >> > The short circuit to the air flow with the cover off is just a few > inches between the heat sink stack and the exhausting case fan, which > exhausts much greater heat than the power supply. A piece of cardboard > or plastic that blocked that short circuit would be an interesting test. > There are actually holes upstream of the CPU to cool the disk drive, > and that air has to get through/around the CPU heat sink to exit the case. > >> My problem has been running high ambient temperatures. With a 90F >> building temp keeping CPU and disk cool is an issue. I looked for a >> Peltier cooler, but didn't come up with one I really liked. And they >> draw a ton of power. > > These boxes have run without air conditioning in summer weather. I > don't think 90F ambient should be a problem. > Now that I look, this system seems to have hit 52C air temp last August. That's air, not components. That sound right for four servers in a room, 102F temp outside, pulling in "cooling" air with a window fan over a hot black roof in full sunlight. As the song says, "Somethin' Got to be Arranged." Google says systems can run hotter, several have been up for 400+ days, so maybe they're right. Hope so. :-(
From: Robert Redelmeier on 29 Jun 2010 13:38 In comp.sys.ibm.pc.hardware.chips Robert Myers <rbmyersusa(a)gmail.com> wrote in part: > Energy efficiency is the new wild card. It's the only consideration > I can imagine that would justify cutting it so close. Older problems, but perhaps related/continuing: http://www.nytimes.com/2010/06/29/technology/29dell.html -- Robert R
From: Robert Myers on 29 Jun 2010 17:16 Robert Redelmeier wrote: > In comp.sys.ibm.pc.hardware.chips Robert Myers <rbmyersusa(a)gmail.com> wrote in part: >> Energy efficiency is the new wild card. It's the only consideration >> I can imagine that would justify cutting it so close. > > Older problems, but perhaps related/continuing: > > http://www.nytimes.com/2010/06/29/technology/29dell.html > A long time before Dell's customer service problems and practices began to get public attention, I had a long go-round with them that told me everything I needed to know about the corporate culture there. I even wrote about it in one of these forums, and Felger Carbon defended Dell as not being the bottom-feeder I characterized it as being. I suspect the (still unidentified) company that built the box causing the current problem was the company that he would have claimed was the bottom feeder. When I finally wrestled Dell to the mat, it turned out that there were six hundred people ahead of me for the replacement part needed (so I had to wait another six months for it), and the customer service rep had to consult a manager before finally agreeing with me that there was something wrong with the hardware, which manifested itself as a clear data-corruption problem. The story reported in the New York Times sounds very similar. While it was still in the PC business, no IBM alum would ever comment on the competitive landscape it faced in that market. As I infer the corporate culture at IBM as it once was, they probably believed that their corporate customers would wise up and stop buying the kind of junk that was being sold at rock-bottom prices. History, of course, proved otherwise. As Yousuf pointed out earlier, it's quite a challenge to build a box at a price that's competitive with what you can get from an OEM, and, even then, although you know exactly who provided each part (at least in theory), you can still wind up with a motherboard that becomes notorious for having been built with bad capacitors. If I had to finger a culprit here, I'd point at the business schools, which seem to be so detached from reality that they actually think that anything that looks good on a spreadsheet is a good business practice. That anyone ever would have admired Dell just boggles my mind, just as it boggles my mind that people *still* don't get why we are so much poorer now than we were a few years ago. That is to say that, although the PC business is cut-throat in a way that ultimately puts customers at risk, it is not a problem that is peculiar to PC OEM's. Robert.
From: Yousuf Khan on 30 Jun 2010 04:02 On 6/29/2010 11:38 PM, Robert Redelmeier wrote: > In comp.sys.ibm.pc.hardware.chips Robert Myers<rbmyersusa(a)gmail.com> wrote in part: >> Energy efficiency is the new wild card. It's the only consideration >> I can imagine that would justify cutting it so close. > > Older problems, but perhaps related/continuing: > > http://www.nytimes.com/2010/06/29/technology/29dell.html Quite the come down for a company which was a model taught at the Harvard business school. But in reality, even back when it was a business darling, people knew they were sitting on a slippery slope. It's real business model lay in the taking of subsidies from bigger companies that acted as its sugar daddy. Yousuf Khan
From: Robert Myers on 7 Jul 2010 00:26
On Jun 22, 4:31 pm, Bill Davidsen <david...(a)tmr.com> wrote: > > Glad you like it, I have been thinking of a 930 for a KVM server, drop in 12GB > of RAM and 4TB of cheap disk and put all the boring little 512m servers on Earth > on it. Everything now goes through this 64-bit Windows desktop, including a virtual 64-bit Fedora 13 and a virtual 32-bit Windows XP Professional, with a Cygwin X-server handling graphical output from other Linux boxes. The virtualized machines, both Windows and Linux running simultaneously, are at least as snappy as Windows and Linux running on E8200 and E8400 Core 2 Duo. I wish someone made affordable 4Gb DDR3 non-ECC, since memory is the only thing that is ever remotely in short supply. The virtualized XP Professional will allow me to decommission a separate box running XP just to support a handful of legacy XP programs. Robert. |