A computer components & hardware forum. HardwareBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » HardwareBanter forum » Processors » Intel
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Marginal OEM Power Supply



 
 
Thread Tools Display Modes
  #1  
Old June 22nd 10, 03:19 PM posted to comp.sys.ibm.pc.hardware.chips,comp.sys.intel
Robert Myers
external usenet poster
 
Posts: 606
Default Marginal OEM Power Supply

Robert Redelmeier wrote:
In comp.sys.ibm.pc.hardware.chips Robert Myers wrote in part:
I had previously noted the puniness of power supplies on OEM
boxes, but not by overloading them to the point where the machine
wouldn't run. I don't think that upping the RAM by 50% and adding
a HDD causing a power supply overload is a reasonable expectation.


Agreed. HDDs (especially 10k) can cause a heavy motor-start
load on the 12V but should otherwise be fine. One problem with
big OEMs is they are also aiming at EPA EnergyStar targets
which cause them to tight-size PSUs for max efficiency.
The German TuV may also have powerfactor targets.

Energy efficiency is the new wild card. It's the only consideration I
can imagine that would justify cutting it so close.


Something else about this machine that is shaved very close is
the thermal design. It will not run for long with the side cover
removed. That wouldn't surprise me if the side cover included a
duct, but there are only holes strategically placed in the side
panel. The CPU has an enormous heat sink, but no fan of its own!


There is your clue, no CPU fan -- the cover is a duct. With the
cover off, air can bypass the CPU heatsink and slip straight to
[from] the PSU fan. I've built machines without CPU fans, and
you have to be very careful about airflow.

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.

Robert.
  #2  
Old June 22nd 10, 09:45 PM posted to comp.sys.ibm.pc.hardware.chips,comp.sys.intel
Bill Davidsen
external usenet poster
 
Posts: 245
Default Marginal OEM Power Supply

Robert Myers wrote:
Robert Redelmeier wrote:
In comp.sys.ibm.pc.hardware.chips Robert Myers
wrote in part:
I had previously noted the puniness of power supplies on OEM
boxes, but not by overloading them to the point where the machine
wouldn't run. I don't think that upping the RAM by 50% and adding
a HDD causing a power supply overload is a reasonable expectation.


Agreed. HDDs (especially 10k) can cause a heavy motor-start
load on the 12V but should otherwise be fine. One problem with
big OEMs is they are also aiming at EPA EnergyStar targets
which cause them to tight-size PSUs for max efficiency.
The German TuV may also have powerfactor targets.

Energy efficiency is the new wild card. It's the only consideration I
can imagine that would justify cutting it so close.


Something else about this machine that is shaved very close is
the thermal design. It will not run for long with the side cover
removed. That wouldn't surprise me if the side cover included a
duct, but there are only holes strategically placed in the side
panel. The CPU has an enormous heat sink, but no fan of its own!


There is your clue, no CPU fan -- the cover is a duct. With the
cover off, air can bypass the CPU heatsink and slip straight to
[from] the PSU fan. I've built machines without CPU fans, and
you have to be very careful about airflow.

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.

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.
  #3  
Old June 23rd 10, 06:33 PM posted to comp.sys.ibm.pc.hardware.chips,comp.sys.intel
Robert Myers
external usenet poster
 
Posts: 606
Default Marginal OEM Power Supply

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.

Robert.
  #4  
Old June 28th 10, 01:54 AM posted to comp.sys.ibm.pc.hardware.chips,comp.sys.intel
Bill Davidsen
external usenet poster
 
Posts: 245
Default Marginal OEM Power Supply

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. :-(
  #5  
Old June 29th 10, 06:38 PM posted to comp.sys.ibm.pc.hardware.chips,comp.sys.intel
Robert Redelmeier
external usenet poster
 
Posts: 316
Default Marginal OEM Power Supply

In comp.sys.ibm.pc.hardware.chips Robert Myers 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/te...gy/29dell.html

-- Robert R

  #6  
Old June 29th 10, 10:16 PM posted to comp.sys.ibm.pc.hardware.chips,comp.sys.intel
Robert Myers
external usenet poster
 
Posts: 606
Default Marginal OEM Power Supply

Robert Redelmeier wrote:
In comp.sys.ibm.pc.hardware.chips Robert Myers 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/te...gy/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.
  #7  
Old June 30th 10, 09:02 AM posted to comp.sys.ibm.pc.hardware.chips,comp.sys.intel
Yousuf Khan[_3_]
external usenet poster
 
Posts: 2
Default Marginal OEM Power Supply

On 6/29/2010 11:38 PM, Robert Redelmeier wrote:
In comp.sys.ibm.pc.hardware.chips Robert 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/te...gy/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
  #8  
Old July 8th 10, 09:23 PM posted to comp.sys.ibm.pc.hardware.chips,comp.sys.intel
chrisv
external usenet poster
 
Posts: 580
Default Marginal OEM Power Supply

Robert Myers wrote:

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,


I don't know... There's worse. I remember years ago having to fight
to get a Dell over a Compaq that was $1,500 more despite being far
inferior (e.g. 486 vs. P90), not to mention that, IMO, desktop Compaqs
were, and still are, garbage.

"You get what you pay for", I heard, always from people who had *zero*
clue about computers.

I've had great success with generic hardware.

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Marginal OEM Power Supply Robert Myers General 28 September 15th 22 05:30 PM
power supply on new build w old power supply ed jurewicz Homebuilt PC's 1 December 19th 07 02:26 PM
Antec TPII 550EPS12V or Cooler Master Real Power 550 power supply??? brian Homebuilt PC's 7 May 6th 05 07:56 AM
Antec TPII 550EPS12V or Cooler Master Real Power 550 power supply??? brian Overclocking 6 May 5th 05 12:21 PM
A marginal Samsung problem r wiley Printers 1 December 28th 03 03:29 AM


All times are GMT +1. The time now is 05:45 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 HardwareBanter.
The comments are property of their posters.