Dell fan speed control
 

I don't know if anyone knows, but I'd like to.

On the "classic" Dell systems that actually had parts inside that were
designed and maybe even assembled by Dell, there is clearly some type of fan
monitoring that is done by the BIOS. If you pull the plug on a fan, the
system will beep unhappily and tell you at POST that a fan is not
responding.

I've looked at a dead Dimension E521 board to see how they might do this, as
looking with software such as SpeedFan shows nothing. I found that this is
because the LPCIO simply doesn't have any fan speed reporting, temperature
reporting or fan control functionality. (Someone thought of using at least
temperature reporting for the E521--there are unpopulated spots on the board
clearly labeled as places for thermal sensors.) This is true of other Dell
systems, such as the Dim8400, 8300, 2400 and OptiPlex 170. (Systems like the
Dimension 2100 and its siblings (L5xx series) have temperature/fan
monitoring functions in their LPCIO ICs, but it isn't used or connected.)

I could not trace the board--it has too many layers. The mechanism for
actual fan speed control is obvious--a temperature sensor bulb that
protrudes into the airflow from the fan will speed it up if it gets hot.

I'd like to know how Dell does fan speed monitoring, and while I suspect
that this may require asking a Dell system board designer how it was done,
I'm hoping that someone on the group might know.

William

Dell fan speed control
 

William,

Your question was, is, and will be actually a 2-part question. Dell used/uses a
lot of Intel-designed motherboards. In the past, many of them have actually
been identical to Intel's own designs, at least, superficially. Others are
minor modifications to Intel designs. For the Intel boards in the Dells, the
trend is obvious. Intel once had very nice monitoring software that ren only on
800-series chipsets and systems with an original generic Intel BIOS (not an OEM
BIOS like Dell's or Gateway's). No longer does Intel provide monitoring
software, and they apparently use for controlling fan RPMs a low-level scheme
something that Speedfan et al cannot detect. For these Intel designed boards, I
will claim that Dell provides exactly zero electronic design engineering
expertise, only very minor variations in board layout and (rarely these days)
cost-tradeoff discussions with Intel whether or not to drop board features.
(Sometimes, it costs more to drop a feature during manufacturing than to keep it
there disabled.) So for Dell boards with Intel designs, someone from Intel is
best equipped to answer your question.

For the non-Intel boards, the other board manufacturers themselves are better
equipped to answer your question.

I would be dumbfounded if Dell's "engineering" contribution to the design and
manufacture of motherboards was much more than I have described above. The
industry has matured to the point where motherboard designs are very much
standardized, as is the manufacturing. There is little or no reason for Dell,
HPaq, Lenovo, Gateway and the rest to have highly paid board designers in house
for desktop boards. Instead, that expertise lies within Intel, Foxconn (actual
mfr of Intel designs), Asus, etc... Ben Myers

On Sat, 04 Oct 2008 05:01:21 GMT, "William R. Walsh"
m wrote:

I don't know if anyone knows, but I'd like to.

On the "classic" Dell systems that actually had parts inside that were
designed and maybe even assembled by Dell, there is clearly some type of fan
monitoring that is done by the BIOS. If you pull the plug on a fan, the
system will beep unhappily and tell you at POST that a fan is not
responding.

I've looked at a dead Dimension E521 board to see how they might do this, as
looking with software such as SpeedFan shows nothing. I found that this is
because the LPCIO simply doesn't have any fan speed reporting, temperature
reporting or fan control functionality. (Someone thought of using at least
temperature reporting for the E521--there are unpopulated spots on the board
clearly labeled as places for thermal sensors.) This is true of other Dell
systems, such as the Dim8400, 8300, 2400 and OptiPlex 170. (Systems like the
Dimension 2100 and its siblings (L5xx series) have temperature/fan
monitoring functions in their LPCIO ICs, but it isn't used or connected.)

I could not trace the board--it has too many layers. The mechanism for
actual fan speed control is obvious--a temperature sensor bulb that
protrudes into the airflow from the fan will speed it up if it gets hot.

I'd like to know how Dell does fan speed monitoring, and while I suspect
that this may require asking a Dell system board designer how it was done,
I'm hoping that someone on the group might know.

William

Dell fan speed control
 

William R. Walsh wrote:
I don't know if anyone knows, but I'd like to.

On the "classic" Dell systems that actually had parts inside that were
designed and maybe even assembled by Dell, there is clearly some type of fan
monitoring that is done by the BIOS. If you pull the plug on a fan, the
system will beep unhappily and tell you at POST that a fan is not
responding.

I've looked at a dead Dimension E521 board to see how they might do this, as
looking with software such as SpeedFan shows nothing. I found that this is
because the LPCIO simply doesn't have any fan speed reporting, temperature
reporting or fan control functionality. (Someone thought of using at least
temperature reporting for the E521--there are unpopulated spots on the board
clearly labeled as places for thermal sensors.) This is true of other Dell
systems, such as the Dim8400, 8300, 2400 and OptiPlex 170. (Systems like the
Dimension 2100 and its siblings (L5xx series) have temperature/fan
monitoring functions in their LPCIO ICs, but it isn't used or connected.)

I could not trace the board--it has too many layers. The mechanism for
actual fan speed control is obvious--a temperature sensor bulb that
protrudes into the airflow from the fan will speed it up if it gets hot.

I'd like to know how Dell does fan speed monitoring, and while I suspect
that this may require asking a Dell system board designer how it was done,
I'm hoping that someone on the group might know.

William



Take a look at the fan and you will see three wires. One is power one is
ground and one is a speed signal (like a tach signal in a vehicle) The
machine powers up and the fan starts to spin. The tach signal starts and
the machine sees that the fan is spinning. It compares the speed to the
speed it last recorded for the fan. If they are withing a certain
percentage it says the fan is OK and the BIOS lets the machine continue.
The thermistor on the fan also watches the air temperature across it,
When the temp goes up the thermistor lets more power through and speeds
up the fan.

--
Steve W.
Near Cooperstown, New York

Life is not like a box of chocolates
it's more like a jar of jalapenos-
what you do today could burn your ass tomorrow!


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Dell fan speed control
 

Hi!

Take a look at the fan and you will see three wires.

I'm pretty good on understanding how the fan does its thing. :-)

What I'd like to know is how Dell monitors it, since the LPCIO has no
explicit support.

William

Dell fan speed control
 

Hi!

Your question was, is, and will be actually a 2-part question. Dell
used/uses
a lot of Intel-designed motherboards.

I think that depends upon which Dell system you look at. Some of the boards
floating around are "distinctly Dell"...I'm thinking of ones where you see
the onboard Broadcom 4401 chipset for Ethernet for my example. On the other
hand, I could see an Intel design being used in the Dim8300--since the
Ethernet is integrated into the chipset.

Intel once had very nice monitoring software that ren only on
800-series chipsets and systems with an original generic Intel BIOS (not
an
OEM BIOS like Dell's or Gateway's). No longer does Intel provide
monitoring
software, and they apparently use for controlling fan RPMs a low-level
scheme
something that Speedfan et al cannot detect.

I've seen this monitoring software (or so I think), and have it on an Intel
board with 8 PCI slots. However, that board definitely has an LPCIO that is
capable of monitoring temperatures, RPMs and voltages. It does show up to
SpeedFan.

The other Intel board that I have is a OEM-for-Gateway D845HV board that
uses an Analog Devices fan controller and an SMSC LPCIO for temperature and
voltage monitoring.

I would be dumbfounded if Dell's "engineering" contribution to the design
and
manufacture of motherboards was much more than I have described above.

I dare say that the manufacturing happens elsewhere, but until recently, I
also had a feeling based on looking at the boards that Dell had at least
some engineers on hand or made significant input into the designs. There was
a common element to most of their motherboard designs that I hadn't seen
anywhere else.

The modern consumer level Dell systems definitely do have fairly generic
boards in them. I found a Foxconn board in an Inspiron desktop, and it does
respond to fan/temperature/voltage monitoring software.

William

Dell fan speed control
 

The tipoff here in recent (i.e. Pentium 4) years has been the presence of an
sticker with an Intel AA "number" on it. Six digits, a hyphen, and 3 more
digits. Except that the high order digit has gone to a hex digit.

No matter what, Dell licenses for motherboard BIOSes give Dell the option to
impose its own distinct look-and-feel on its BIOSes. I view this as a somewhat
forumulaic cookie cutter operation for the BIOS programmers. No software design
expertise needed.

With some of the recent motherboards, Intel models now use Realtak 10/100/1000
chips, giving us a signal that Intel will soon exit from the Ethernet chip
business, if it has not done so already... Ben Myers

On Sun, 05 Oct 2008 05:29:49 GMT, "William R. Walsh"
m wrote:

Hi!

Your question was, is, and will be actually a 2-part question. Dell
used/uses
a lot of Intel-designed motherboards.

I think that depends upon which Dell system you look at. Some of the boards
floating around are "distinctly Dell"...I'm thinking of ones where you see
the onboard Broadcom 4401 chipset for Ethernet for my example. On the other
hand, I could see an Intel design being used in the Dim8300--since the
Ethernet is integrated into the chipset.

SNIP