Two (or more) fans on the same motherboard fan connector

[DanielEKFA]

Hi there

I was hoping someone could help me clarify if this idea I got is a good one
or not. Yesterday, I just got a Thermalright Ultra 120 CPU cooler to which I
can attach two 12-inch fans. I'd like the motherboard (an ASUS P5K-E
WiFi/AP) to be able to throttle these two fans in the same way it did the
stock cooler's fan, so that when the CPU is cool, I get as little noise as
possible, while when it runs hot, it'll throttle up the fans to more
effectively cool down the CPU.

Thing is, it's not like there's two connectors for the CPU cooler's fans,
there's just the one. Now, I was thinking that it might be possible to
simply connect both fans to the same connector. But then I thought, "how
would that affect the fan rotation readings," which, AFAICT, are read
through the yellow wire, while the black and red are ground and +12V
respectively.

Then I start thinking about how this throttling is done in the first place,
and I'm *guessing* that the yellow wire reports back rotational speed in
some way, while some mechanism lowers the voltage (or something equivalent
to that) on the power wires, effectively controlling the fan. So, I'm
thinking I could just share the ground and +12V wires between two fans,
while using just one's yellow wire to report back speed.

Okay, so my questions are the following:
A) Would this work? (I realize that I'd only be able to detect the possible
death of the one fan which is connected to the yellow wire, but as they're
both cooling the same object, I'm willing to accept this)
B) Would the motherboard be able to support this, power consumption wise,
i.e. would I be in risk of blowing out a capacitor or worse? How many watts
would be safe to draw from these onboard connectors?

Thanks in advance for any feedback

Daniel

 

[GT]

Hi there

I was hoping someone could help me clarify if this idea I got is a good
one or not. Yesterday, I just got a Thermalright Ultra 120 CPU cooler to
which I can attach two 12-inch fans. I'd like the motherboard (an ASUS
P5K-E WiFi/AP) to be able to throttle these two fans in the same way it
did the stock cooler's fan, so that when the CPU is cool, I get as little
noise as possible, while when it runs hot, it'll throttle up the fans to
more effectively cool down the CPU.

Thing is, it's not like there's two connectors for the CPU cooler's fans,
there's just the one. Now, I was thinking that it might be possible to
simply connect both fans to the same connector. But then I thought, "how
would that affect the fan rotation readings," which, AFAICT, are read
through the yellow wire, while the black and red are ground and +12V
respectively.

Then I start thinking about how this throttling is done in the first
place, and I'm *guessing* that the yellow wire reports back rotational
speed in some way, while some mechanism lowers the voltage (or something
equivalent to that) on the power wires, effectively controlling the fan.
So, I'm thinking I could just share the ground and +12V wires between two
fans, while using just one's yellow wire to report back speed.

Okay, so my questions are the following:
A) Would this work? (I realize that I'd only be able to detect the
possible death of the one fan which is connected to the yellow wire, but
as they're both cooling the same object, I'm willing to accept this)
B) Would the motherboard be able to support this, power consumption wise,
i.e. would I be in risk of blowing out a capacitor or worse? How many
watts would be safe to draw from these onboard connectors?

A few things:
1. Why not try the cooler with just 1 fan to start with and see what the
performance is like. That way no wiring will be required.

2. Your assumptions about the yellow wire is correct - an RPM signal. The
BIOS controls the fan speed according to temperature of the CPU. When it
reaches a certain temperature threshold (normally also set in the BIOS), the
fan will speed up until the temperature drops below again.

3. Your solution for wiring 2 fans would effectively wire the 2 fans in
parallel, so they would both run at the same voltage, but you would double
the current required. I can't say whether that would be a problem or not -
that all depends on the circuitry and fusing on the motherboard for the CPU
fan connector. My gut instinct tells me that it would be fine. But, use the
yellow wire from just 1 fan.

 

[Angelo Campanella]

A) Would this work?

Basically, it's a great ide, but the devil is in the details.

(I realize that I'd only be able to detect the
possible death of the one fan which is connected to the yellow wire, but
as they're both cooling the same object, I'm willing to accept this)
B) Would the motherboard be able to support this, power consumption
wise, i.e. would I be in risk of blowing out a capacitor or worse? How
many watts would be safe to draw from these onboard connectors?

The RPM signal (yellow wire) signal from the second fan might be
terribly confusing and will cause erroneous control. But then it might
not depending on the RPM logic... nobody nows for sure. It is best to
connect black and red wires only to the new fan, and let the new fans
rum at whatever RPM the partial voltage leads them to; no big deal.

If my understanding is correct, the red wire does not see exactly 12
volts but something lower depending on what the control circuit feeds
it. You propose to feed the red wire of the second fan from the red
terminal of the first fan. That assumes that both fans are alike. If
they both expect 12v for full throttle, then it's more likely so. If the
extra fans pull the same current or more curent, then it is likely that
the motherboard power supply will not carry all fans, certainly not at
maximum cooling power. If the new fans require less current than the
original CPU fan, it will likely work just fine.

For new fans drawing more current, a separate current feeding supply
should be installed. If the applied voltage is switched (either 12v or
zero in rapid succession) then your new control circuit is easy and
cool. If it is analog partial voltage, then heat dissipation within your
new control circuit will need to be considered (heat sink, etc). It is
possible that where current switching (full 12 volts, part time) is
used, it is at an ultrosound rate, then smoothed by a capacitor before
being fed to the fan motor. Using this smoothed external signal for your
control circuit results in an analog circuit requiring a heat sink. It
is also possiblte that the switching is at a low frequency, and that you
can use that as a new switched control signal. Put a scope on the 12v
terminal and determine which it is.

Another possibility is to simply run the new fans at one reduced
voltage (e.g. 5 volts), for low RPM silent operation. At least start out
that way. Another possibllty is to run the two new fans in series,
giving 6 volts each for the same result.

Angelo Campanella

 

[GT]

Basically, it's a great ide, but the devil is in the details.


The RPM signal (yellow wire) signal from the second fan might be terribly
confusing and will cause erroneous control. But then it might not
depending on the RPM logic... nobody nows for sure. It is best to connect
black and red wires only to the new fan, and let the new fans rum at
whatever RPM the partial voltage leads them to; no big deal.

The yellow (RPM) wire is not used to control the fan throttling system. The
fan speed is controlled by CPU temperature and threshold values in the BIOS.
There is a warning on fan rotation speed which can be set to 'alarm' or
'shutdown system' or 'disabled'. So getting a speed reading from just 1 fan
would be fine and shouldn't cause confusion

 

[DanielEKFA]

Hi GT and Angelo, and thanks for all your very informative replies

I got a bit impatient with the whole thing, I really wanted to do it, so I
just thought, well, I might as well try, worst thing I'll wreck the mobo

So, I basically just did it the way I believed it to work. An indeed it does
work! Both fans are happily spinning (quite silently) and keeping the CPU
really, I mean, REALLY cool.

I hadn't thought about the fans preferably being the same type, but luckily
enough, they're exactly the same (came with my case), so probably I won't
get any weird behavior on that account.

On a side note, reading up on the connectors and wires prior to this, I
found out that the "7V trick" to slow fans down is not always so good on
one's PSU, and I had five fans connected like that in my case! So, I pulled
out those and replaced them with just one fan running at 12V. Hopefully that
will clear up some weirdness I've been having with a couple of drives.

I don't know if the two fans running on the same connector will cause them
to run slower when maxing out, but here in idle they run at the same speed
as before, when one was connected to a chassis connector. Either way, with
the temps I'm having ATM, I don't think it'll be much of an issue

I don't really understand the stuff Angelo writes at the end of his message,
with the scope and all, but is it very important? Or, now that it runs
(seemingly fine) have I, without knowing it, proved the risky way that it is
switched, analog partial, or smoothed, if those are even different?

Sorry, not that skilled in electronics, I can handle a soldering iron and
give myself some electric shock now and then, but the theoretical stuff is
pretty much unchartered territory to me

Once again, thanks for your help!

Cheers,
Daniel

 

[Paul]

Hi there

I was hoping someone could help me clarify if this idea I got is a good
one or not. Yesterday, I just got a Thermalright Ultra 120 CPU cooler to
which I can attach two 12-inch fans. I'd like the motherboard (an ASUS
P5K-E WiFi/AP) to be able to throttle these two fans in the same way it
did the stock cooler's fan, so that when the CPU is cool, I get as
little noise as possible, while when it runs hot, it'll throttle up the
fans to more effectively cool down the CPU.

Thing is, it's not like there's two connectors for the CPU cooler's
fans, there's just the one. Now, I was thinking that it might be
possible to simply connect both fans to the same connector. But then I
thought, "how would that affect the fan rotation readings," which,
AFAICT, are read through the yellow wire, while the black and red are
ground and +12V respectively.

Then I start thinking about how this throttling is done in the first
place, and I'm *guessing* that the yellow wire reports back rotational
speed in some way, while some mechanism lowers the voltage (or something
equivalent to that) on the power wires, effectively controlling the fan.
So, I'm thinking I could just share the ground and +12V wires between
two fans, while using just one's yellow wire to report back speed.

Okay, so my questions are the following:
A) Would this work? (I realize that I'd only be able to detect the
possible death of the one fan which is connected to the yellow wire, but
as they're both cooling the same object, I'm willing to accept this)
B) Would the motherboard be able to support this, power consumption
wise, i.e. would I be in risk of blowing out a capacitor or worse? How
many watts would be safe to draw from these onboard connectors?

Thanks in advance for any feedback

Daniel

There are four fan headers on that motherboard. You can run the RPM wire from
one fan, to one of those unused chassis fan headers. The RPM wire from the
second fan, can continue to be connected to the four pin CPU fan header. (I.e.
You'd use two fan headers, to monitor two RPM signals.)

Q-fan, as far as I know, is not a closed loop system - the chip controlling
the speed of the fan, does not check to see if the fan is following commands
or not. There will be a check for "zero RPM", which is a threshold value, but
other than that, Q-fan delivers a voltage in response to the measured
temperature. It doesn't care what RPM the fan responds with, when the
voltage is applied.

The motherboard has no selection function in the BIOS, for three pin versus
four pin control method. The motherboard doesn't appear to support the old
12V control method. It looks like a PWM-only CPU-fan header. That means,
a retail Intel fan, having the four pin interface, listens to the PWM
signal, and the speed is controlled that way.

The fans you've placed on your cooler, could be three pin fans, which means
right now, they probably don't demonstrate any control at all. If you connect
one of them as a test, it would probably running at full speed no matter
how Q-fan is configured for the CPU-Fan.

The following, is a PWM fan 120mmx120mm and 25mm thick. At full bore, it is
96CFM, and that would probably be pretty loud. Since it is PWM, connecting
it will be easy. The PWM output of the motherboard, can be connected to
more than one fan in parallel. So no circuitry needs to be designed, to
do this. It is just wiring.

Rexflo DF1212025BH-PWMG 120mm Case Fan - 96 CFM 42.60 dBA 12V at 0.3A - 4 pin w. PWM. $18
http://www.newegg.com/Product/Product.aspx?Item=N82E16835705025
http://rexususa.com/fans/21225-4.html


CPU-FAN PWM -----------------------------+------------------------+
| |
PWM-Fan1 PWM-Fan2

RPM -----------------------------+
|
RPM-Fan1

+12V -----------------------------+------------------------+
| |
+12V-Fan1 +12V-Fan2

GND -----------------------------+------------------------+
| |
GND-Fan1 GND-Fan2

Spare-Chassis-Fan-Header

RPM ------------------------------------------------------+
|
RPM-Fan2

For the +12V and GND, those don't even have to come from the CPU-FAN header,
if you don't want. They can also come from a Molex disk drive cable, as it
has +12V and GND. That is an alternative, if you think the fans will draw
too much current for the motherboard rating. Since the above Rexflo 120mm
fan is 12V @ 0.3A, two of those at 0.6A is probably OK. The motherboard
manual claims up to 2 amps can come from a fan header, which seems a
bit aggressive on their part. So the 0.6A total is probably not too
much, if you want to run both fans using the +12V and GND pins of the
CPU fan header.

So nothing needs to be designed, if you can find a PWM equipped fan like
the Rexflo above. Just a matter of doing some wiring. It helps if you
have an electronics store, that happens to carry fan connectors. I got
a bag of pins and the plastic 3-hole bodies, so I can make my own three pin
ends when I need them. You'd need a three pin end, to make the single wire and
connector needed for the "Spare-Chassis-Fan-Header" connection.

Otherwise, the wiring of the other two fans, can be done with the
harnesses already on them. You could even chop off the four pin on
one Rexflo fan, and use it as a mechanism to make the connection to the
"Spare-Chassis-Fan-Header", but it would look a bit ugly having
a four pin connector on a three pin header. You might forget how it
should be oriented, and it might fall off some day.

HTH,
Paul

 

[GT]

Normally this is true, but it wouldn't be impossible (and to
some, even a more desirable way to implement the fan
control) if the RPM signal were used to determine and change
fan RPM to a threshold level. For example, at 50C, do what
is needed to make fan RPM 3000.

Absolutely - not impossible, but that would require the BIOS to have
knowledge of the thermal dissipation power of the heatsink and the CFM of
the fan, plus one or two other values concerning case temperature and
airflow through the heatsink. Not as simple as you think.

 

[GT]

Not necessarily... you're still trying to think in terms of
"try to keep the CPU at the same temperature", which is not
necessary. The only thing truely necessary is to keep it
below an absolute maximum threshold value which could still
be programmically forced as (use max fan power @ threshold
temp).

No, I'm talking about turning up the fan speed when the temperature goes
over a certain threshold, but how would the BIOS know what voltages to turn
the fans up/down to?

Regardless of the actual temperature goal, the fan speed is controlled by
varying the voltage. The BIOS has no information about the heat dissipation
characteristics of the heatsink (it doesn't know what heatsink is on there)
and the amount of additional cooling provided by turning the fan up and down
(it doesn't know what the fan's flowrate is and how efficiently that airflow
actually cools the heatsink), so it therefore won't 'know' what voltage to
give the fan to achieve the required level of cooling.

My point is that different fans move different amounts of air at different
voltages - take a standard 775 cooler with a single 90mm fan versus the twin
120mm fan setup we are talking about here. If the BIOS sets the fans at 7v,
the 90mm fan will shift something like 10-20cfm, but the twin 120mm fans at
7v will shift something like 60-80cfm. This extra airflow will cool the
heatsink considerably more, but how will the BIOS know this? The BIOS would
have to 'experiemnt' and store values to calibrate itself to do what you are
suggesting. However, this would not be complicated and is a good idea!

 

[DanielEKFA]

As you reported in your subsequent post, the processor runs
really cool... ok, but is this at full load? The
distinction is, full load is the more important parameter
and unless you are overclocking a lot, you should not need
two 120mm fans on that heatsink, would be making this more
complex than necessary, perhaps more complex than beneficial
since a CPU doesn't need to run as cool as possible, only
cool enough to stay stable and promote good lifespan (which
is many years longer than you'd be likely to use it).

Hey Kony, sorry for this superslow reply, I kinda went off the grid there
for awhile. Nothing related to my little project here, though

Actually, I am overclocking it. I started out briefly with just one fan,
then decided to put in two, adding a third to the case immediately next to
the heatsink. Doing this (and removing another fan which actually PREVENTED
good airflow) temps dropped massively, about 15*C.

My aim was to push it as high as the temperature would allow it to run
stable, then back off a bit to allow summer to come without crashing my
system I dropped 300 MHz from the absolutely max stable overclock to an
OC of 3.3GHz (stock is 2.4). ATM, temps run up past 70*C on the cores if
running Prime for very long periods of time. I have no problem with this
temp, I know it'll cost some of the processors expected lifespan, but as you
also point out, fat chance I'll be using it at that time anyway. For what
it's worth, I've overclocked all my previous processors and never had one
burn out on me over time, including my old Athlon and PII.

The sample rate the board uses to detect RPM would determine
how much of these overlapping RPM signals would be detected.
It would tend to register higher than the RPM of one fan,
but possibly not a summary total of both fans' RPM. It
would be an undesirable result either way so one of the
fan's RPM leads would be isolated, not plugged in.

I thought so too, well, actually I knew squat about what would happen if I
used both wires, so I just connected one of them. Both fans are identical,
and they're connected each on one side of the heatsink, and the air is
passing through both of them, so I really can't see that they could be
running at different speeds anyway. Unless one loses a fin or something, but
they're both in perfect shape. I mean, even if one would have a higher
resistance (as in more friction in the movable parts) and thus require more
power to run at a particular speed, I imagine the other fan would be
"helping" by either pushing more air towards the fan or sucking more air
from it, using its excess sucking/blowing capability at any given power to
indirectly speed up the other, less efficient, fan.

Yes, but what you lose is the fine level of control
possible. There is a minimum and maximum RPM the fan
controller circuit could cause with a given fan, then when
having a second one the minimum is still possible, but is a
higher duty cycle of the entire possible control range per
the same fan(s) RPM, and the maximum power the circuit can
deliver is still the same so it's roughly divided between
the two fans - you can't have both fans spinning at full RPM
that (only) one would have if the system were to get hot
enough to cause the circuit to try to output full power.

I really don't understand what this means...

This could effectively cancel most of the gain in having two
fans, but to back up a moment we would also want to consider
if the two fan combo, or one fan alone, would ever run at
full RPM - if the CPU ever got hot enough to cause that
which it may not, especially not if you aren't overclocking
and it's a typical room temp, decent case cooling.

I think the system tries to run them at full throttle when the temp maxes
out in Prime, but I can't say if it's able to or not. I can really hear them
work though, which I can't when it runs idle or when I'm just doing normal
work. Either way, they're really, really effective. It's a fantastic
heatsink. Running at max temp, full load, cores at ~70*C, when I stop Prime,
temp drops as much as 25*C by the next of the readings, which tick by at one
per second! Suffice to say, I'm really content

Yes you will retain a certain level of control, just a lower
max RPM, and the steps of increase (a granular increase
typically, not truely linear compared to infinitely small
steps in CPU temp increase) would be broader. In practice
it may not matter so much because a CPU tends to change temp
rapidly going from mostly idle to mostly loaded, seldom
would it stay around 30% load for example, unless you had a
very fixed scenario like encoding a video in realtime as it
came in over a streaming (cable TV or whatever) connection.

That's true. I imagine, since it's a quad core, that probably a
single-threaded app running at max would produce a similar scenario? Either
way, in these cases, the system still runs cool and quiet. Even when doing
four-threaded x264 video encoding, the system is able to remain relatively
cool and noiseless, as the encoder seems to "burst" usage, then drop a
little, then burst again, repeatedly, giving the cpu little "breathers",
which really really shows the quality of this heatsink, as it just manages
to keep it impressively cool in this scenario.

By the way, I'm not affiliated with ThermalRight Hehe

The fan control circuit is typically consisting of an opamp
driving a transistor. It would be possible to overheat the
transistor if it weren't 'sunk to a large enough area of the
board copper or if case temp was very high, but it's largely
a matter of just how much current you're using, how power
hungry these fans are at max output. Generally, a fan trace
going to some header elsewhere on the motherboard is good
for about 500mA max, but for the CPU it can depend on the
board design, it might be only 500mA total or could be quite
higher in capacity.

Under no situation would you blow out a capacitor with this
config, it'd be the transistor or a copper trace
delaminating, oxidizing or burning through over time. If
your fans are each rated for about 350mA or less it does not
seem likely to be possible to cause a problem, fans tend to
be rated for peak current while above I'm speaking of
continuous current. Since the fan control circuit is, by
design, limiting current, in a normal throttled operating
mode it would likely be safe to use fans rated for even
upwards of 1A peak power but to be conservative there is no
need to test or risk this, certainly no need to have such a
fan let alone a pair of them for processor cooling.

Good to hear. Also, the case is very large (Lian Li tower), and has a
seperated space for harddrives with its own airflow, so the case itself runs
very cool. In the "non-harddrive" area of the case I only have the
motherboard, processor, graphics card, and a couple of SATA controller
cards - no drives at all - so the only real heat dissipator adding to case
heat would be the processor (since the graphics card blows out its used air
behind the case, not inside). I think the separation of the hard drives to
their own compartment is one of the best features of this case. With the 14
harddrives I have, I very very much doubt I'd be able to keep the case
temperature at any reasonable level, even without overclocking.

Personally I would do as suggested above, remove one fan and
see how hot the system gets... keeping in mind that you may
have bios or software control over what the fan RPM vs temp
threshold is. I usually like to keep my 'sink fan running
at minimum RPM until CPU has exceeded 50C, sometimes higher
depending on the situation. If you only have one fan header
that has variable control, it could even be as desirable (if
you really want it to control two fans) to control one fan
on the heatsink and one fan on the case exhaust... otherwise
having the case exhaust fan at a fixed speed it isn't
responding to removal of the heat from the case in a
corresponding matter to heat generation.

I'm not sure exactly why I got such a great heatsink performance gain from
adding the second fan to the heatsink. Maybe it's because it then tends to
get more air from outside the case rather than inside, maybe because the air
passes more directly over the fins. Dunno, but I'm happy

Thanks for your input!

Daniel

 

[DanielEKFA]

There are four fan headers on that motherboard. You can run the RPM wire
from
one fan, to one of those unused chassis fan headers. The RPM wire from the
second fan, can continue to be connected to the four pin CPU fan header.
(I.e.
You'd use two fan headers, to monitor two RPM signals.)

Q-fan, as far as I know, is not a closed loop system - the chip
controlling
the speed of the fan, does not check to see if the fan is following
commands
or not. There will be a check for "zero RPM", which is a threshold value,
but
other than that, Q-fan delivers a voltage in response to the measured
temperature. It doesn't care what RPM the fan responds with, when the
voltage is applied.

Hi Paul, thanks for your input

I'm hesitant in following this route, because I don't really see how the
system would be able to throttle correctly. I mean, with one fan on the case
connector, that fan would throttle with respect to case temperature, not CPU
temperature. So, if case temperatures are low and CPU temperature is high,
the system will try to lower the airflow through the case fan while
hightening the airflow through the CPU fan, so basically the fans would "get
in each other's way", no?

The motherboard has no selection function in the BIOS, for three pin
versus
four pin control method. The motherboard doesn't appear to support the old
12V control method. It looks like a PWM-only CPU-fan header. That means,
a retail Intel fan, having the four pin interface, listens to the PWM
signal, and the speed is controlled that way.

The fans you've placed on your cooler, could be three pin fans, which
means
right now, they probably don't demonstrate any control at all. If you
connect
one of them as a test, it would probably running at full speed no matter
how Q-fan is configured for the CPU-Fan.

This is what I thought, too. And, testing, I cannot manually control the
fans, neither by way of the BIOS nor by way of software. But, they do
control themselves, oddly. I'm not sure what the explanation is (if any,
maybe the BIOS and the software just suck), but I can confirm by readings
(and the noise from the fans) that they speed up as needed when the load
gets high and temperatures rise. Which is good, I think, since I really
didn't want some software controlling this in the first place, if there was
a hardware alternative.

The following, is a PWM fan 120mmx120mm and 25mm thick. At full bore, it
is
96CFM, and that would probably be pretty loud. Since it is PWM, connecting
it will be easy. The PWM output of the motherboard, can be connected to
more than one fan in parallel. So no circuitry needs to be designed, to
do this. It is just wiring.

Rexflo DF1212025BH-PWMG 120mm Case Fan - 96 CFM 42.60 dBA 12V at 0.3A - 4
pin w. PWM. $18
http://www.newegg.com/Product/Product.aspx?Item=N82E16835705025
http://rexususa.com/fans/21225-4.html


CPU-FAN PWM -----------------------------+------------------------+
| |
PWM-Fan1
PWM-Fan2

RPM -----------------------------+
|
RPM-Fan1

+12V -----------------------------+------------------------+
| |
+12V-Fan1
+12V-Fan2

GND -----------------------------+------------------------+
| |
GND-Fan1
GND-Fan2

Spare-Chassis-Fan-Header

RPM ------------------------------------------------------+
|

RPM-Fan2

For the +12V and GND, those don't even have to come from the CPU-FAN
header,
if you don't want. They can also come from a Molex disk drive cable, as it
has +12V and GND. That is an alternative, if you think the fans will draw
too much current for the motherboard rating. Since the above Rexflo 120mm
fan is 12V @ 0.3A, two of those at 0.6A is probably OK. The motherboard
manual claims up to 2 amps can come from a fan header, which seems a
bit aggressive on their part. So the 0.6A total is probably not too
much, if you want to run both fans using the +12V and GND pins of the
CPU fan header.

That is really good to know - I was really curious as to whether there was a
way to draw the current from one of the cables from the PSU. But, with 2
amps being available on the fan headers (wow!), that really calms me, too

So nothing needs to be designed, if you can find a PWM equipped fan like
the Rexflo above. Just a matter of doing some wiring. It helps if you
have an electronics store, that happens to carry fan connectors. I got
a bag of pins and the plastic 3-hole bodies, so I can make my own three
pin
ends when I need them. You'd need a three pin end, to make the single wire
and
connector needed for the "Spare-Chassis-Fan-Header" connection.

I need to get some of those, too. Man, it sucks trying to reuse pins and
plastic thingies from old broken hardware Have a great electronics store,
too, although they tend to be a bit expensive on the fans.

Otherwise, the wiring of the other two fans, can be done with the
harnesses already on them. You could even chop off the four pin on
one Rexflo fan, and use it as a mechanism to make the connection to the
"Spare-Chassis-Fan-Header", but it would look a bit ugly having
a four pin connector on a three pin header. You might forget how it
should be oriented, and it might fall off some day.

HTH,
Paul

Indeed it ded Thank you very much, Paul!

Cheers,
Daniel

 

[Paul]

This is what I thought, too. And, testing, I cannot manually control the
fans, neither by way of the BIOS nor by way of software. But, they do
control themselves, oddly. I'm not sure what the explanation is (if any,
maybe the BIOS and the software just suck), but I can confirm by
readings (and the noise from the fans) that they speed up as needed when
the load gets high and temperatures rise. Which is good, I think, since
I really didn't want some software controlling this in the first place,
if there was a hardware alternative.

It is possible for fans to have a thermistor in the hub. For a processor
fan, that makes them sensitive to the chassis air temperature, so the
CPU fan speeds up when the chassis gets warmer.

Paul

 

[DanielEKFA]

The more current they use, the more the controller
percentage becomes less effective in setting a full range of
change from very low RPM to very high. It also varies per
fan, some fans run to a much lower voltage than others and I
don't know about those particular fans.

Hmm... So, in more "Daniel-friendly" terms, there's sort of a max to the
amount of power the system would/could provide on the connector (either as a
result of logic or restrictions) that, because I have two fans to share this
power, they won't be blowing as much as one would were it the lone fan on
the connector?

It is a good result, though I think I would go a different
route and drop vcore a notch or two and aim for the highest
o'c the next lower vcore allows...

That's pretty much what I did The last 300 MHz (@ 3.6GHz which was a
beautiful overclock just because of the fact that it was +50%) needed sooo
much voltage, but I went there anyway because I believe in first going
really extreme on the volts to find the crosspoint (or whatever you'd call
it in English) where volts get just high enough to allow the CPU to run
stable on higher temps while at the same time causing temps that are just
barely not setting the system aflame, then backing off to a more sane
setting (if overclocking can be said to be sane , basically by lowering
the volts to what seems reasonable, then start decreasing FSB to keep the
system from crashing. And then, when that is achieved, to shave off just a
bit more to make the system more accepting of changing ambient temperatures.
I find that the temps are the main reason a CPU crashes (although I read
something about voltage-induced electron jumps or something like that with
the newer, really tiny, wafer resolutions), and that while a higher voltage
will raise the temp threshold at which the CPU starts malfunctioning, it'll
also raise temps quite a lot. There's this magic zone where the increased
voltage is low enough to not cause too high temps while giving just enough
juice to accept a rather elevated temp. And the more volts the processor is
supplied, the more sensitive it is to temps. Which is where the sink comes
in. With the stock sink, above 3GHz was a no-go, and while it didn't require
much extra juice, the temps were really unnerving - but still stable! Now, I
have more juice, +.3G on the speed, and lower temps.

in an effort to lower
noise some when running at full load, but I don't know how
often you run at full load- I am often RARing up things or
doing video jobs that would make that happen. Then again,
for these same jobs the extra performance helps the most if
you're waiting on the job to finish, it's just that I'm
usually not waiting on the result before moving on to do
something else in the interim.

On a completely different subject - I've always sworn by RAR, but have you
tried the open-source 7-Zip lately? The LZMA solid compression with 64MB
dictionary compresses MUCH better than RAR, and amazingly enough, it's
faster too! I recommend you to check it out. (But beware, at 64MB dict, it
uses 709MB while compressing). Doesn't support recovery data though, so
you'll have to par up your archives if you use that.

Yes, though we would hope you can move away from any single
threaded apps that run at 100% load for extended period as
it's a loss of the largest benefits of the quad core CPU.

Yeah, but while I'm stuck with the Windows scheduler and programs are still
single-threaded, it's great to have more cores and run a completely
responsive system while some app is running at 100% I have a single-core
ULV 1GHz notebook, and Windows is just a pain on it. Linux runs great,
though. I don't know exactly how the schedulers differ, but man, they do!

That seems strange, I would wonder if there is another
bottleneck, maybe drive performance?

I don't think so, my guess is actually AviSynth, or the video decoder for
the input medium. The one I referred to here was a VC-1 HDDVD transport
stream, and it was Lanczos resized in AviSynth (could be it, if it's
single-threaded, although I doubt that it could use up a 3.3GHz core all by
itself). Fed as a DirectShow source, so maybe the decoder in ffdshow was
single-threaded, although I doubt that, too. Maybe it's just some memory
operations - I do use exhaustive searches and tons of reference frames,
including B-frames, so I imagine it has to keep quite a large dictionary in
memory while encoding, at least much more that will fit in the on-die
memory. Either way, I actually like this effect, since, even though the CPU
is stable under Prime, it just doesn't feel as comforting when it runs for
days at 100% encoding video. It's nice to know it gets to breathe out once
in a while

I've been a fan of their 'sinks since the Athlon XP era,
though in the last couple years with so many other 'sinks
being made with heatpipes, and a lot of my costly
Thermalright 'sinks now looking like fancy paperweights, I'm
getting away from high end heatsinks and just going for good
value. Newegg has had some pretty good deals on their
Rosewills and Arctic Cooling products, typically under $20
after a rebate, some almost free. The fans that come with
those are sometimes junk but I have more spare fans than I
know what to do with.

Hehe, yeah, I know the feeling, and I agree. I must say that the decision
this time was part boredom, part wanting to just get the temps and noise
levels down, part fascination with overclocking - it really IS a lot of fun
But you won't ever see me buying a liquid cooling system. That's just
plain silly

There are a couple other benefits with the 2nd fan, that it
will tend to help direct the exhaust towards the rear case
fan (if 'sink is situated in line with it) to expell more
dust, and the 2nd fan adds redundancy as well as lower RPM
per at any heat load less than the theshold for full power-
lowering bearing wear.

That's good! Come to think of it, the RPM readings are really low... So if
that means less wear, it would also mean less chance of breaking. Lost a
bunch of harddrives once because I didn't discover a broken fan. Plus, if
one fails, I'd probably just find out by the system crashing under load,
because just one won't cool as efficiently, but it'll probably prevent
serious damage.

 

[DanielEKFA]

It is possible for fans to have a thermistor in the hub. For a processor
fan, that makes them sensitive to the chassis air temperature, so the
CPU fan speeds up when the chassis gets warmer.

I don't think that's it here... These are actually case fans. And they speed
up very quickly when the processor gets hot, much before the case gets hot.
I'm thinking it's the BIOS that's doing it. It has settings for auto, low,
high, mid, and I set it at auto, but setting it at high doesn't increase the
RPM. Maybe it doesn't mean "high rotation", but rather something like "high
efficiency", but that doesn't explain what the "auto" would mean... Hmmm...

 

[DanielEKFA]

True but it can be tricky getting a good match between such
a fan and a mobo integral controller, can cause unintended
stopping of the fan... especially when many of the
thermistor controlled fans seem to have been set up to ramp
in temp at a much higher temp than case air would reach. I
thought once about hacking such a fan by putting 3 higher
value and/or lower threshold thermistors in parallel to
replace the original but the ideal of doing it never seemed
important enough to devote the time.

Maybe this is what the high/low/auto/mid setting controls? Sort of like high
for keeping your system as cool as possible (although that would imply just
maxing out all fans), and auto being the BIOS using some piece of logic to
find out how cool the system should be now... Maybe some sort of weighing
different temp readings... I don't know, seems pretty difficult

 

[Joel]

I don't think that's it here... These are actually case fans. And they speed
up very quickly when the processor gets hot, much before the case gets hot.
I'm thinking it's the BIOS that's doing it. It has settings for auto, low,
high, mid, and I set it at auto, but setting it at high doesn't increase the
RPM. Maybe it doesn't mean "high rotation", but rather something like "high
efficiency", but that doesn't explain what the "auto" would mean... Hmmm...

Me, with very limited knowledge of current technology (getting little too
old to keep up with newer and better technologies), I believe (base on my
very own experience).

CPU fan -most if not all newer mboard has built-in option to control the fan
speed by temperature, and in CMOS setting.

CASE fan(s) - none of my systems has option to control the case fan by
temperature, but it's possible that some newer fan may have built-in its own
option to measure the temperature to in/decrease the speed fan which I don't
have to confirm.

But because I have been running my system(s) almost 365/year, or I only
reboot to refresh the memory once every few weeks, so I have around 4 pretty
powerful case fans to keep the system cool. And the fan speed is controlled
by Fan Controller, and because they are very powerul so they make quite a
bit of noise, so I use the controller to reduce the speed to little under
1/2 power.

 

[larry moe 'n curly]

I cannot manually control the
fans, neither by way of the BIOS nor by way of software. But, they do
control themselves, oddly. I'm not sure what the explanation is (if any,

I control my fans with nothing but LM339 quad comparators hooked to
thermistors and output transistors, but pulse-width modulators aren't
that hard to build. I wouldn't trust putting much of a load on any
mobo's fan headers because their fan controller chips aren't designed
to put out much current, maybe only 500mA, and their outputs don't
seem to be protected very well against overcurrent. Sometimes you can
salvage a blown output by connecting it to a buffer (transistor), but
I wouldn't expect it to work for outputs that vary their voltages,
only outputs that pulse the voltages full-on or full-off.

All DC brushless fans seem to be rated to to work at half their rated
voltage, but they can usually run at 1.0-1.5V less, if given a brief
boost during start-up, such as with a capacitor wired across the
thermistor.

www.maxim-ic.com makes fan controller chips and has lots of easy-to-
understand guides about them.

 

[DanielEKFA]

You are misunderstanding, I would still o'c less so the
result is that the system didn't need to get as loud at full
load, but this is only a personal preference.

Not an issue here. Firstly, the fans usually spin at less than 1k, secondly,
my computer is in the kitchen, with cables going through a hole in the wall
into my bedroom/study Got the idea a while back when I used this
terrible, terrible HSF for my Athlon which sounded (literally!) like a
vaccuum cleaner (I forget its name, but it was top-of-the-pops at the
time) It's a really nice setup when you run 24/7, you just close the door
and all is silent

I like the idea of recovery data, though you do make 7-Zip
sound interesting. How much of an improvement is there
using the larger dictionary? It seems almost too large,
often I que up such things on lesser systems which would
otherwise have no need for that (709MB) much memory.

There's a comparison here:
http://en.wikipedia.org/wiki/Data_compression#Comparative

Doesn't seem to take different dict sizes into account, though. Probably the
results there are with a 4M dictionary, and non-solid (well, the size of the
data to compressed doesn't really call for much more than a 4M dict .

My own experience is that it generally, and always, compresses better than
RAR, and at about 1.5-2x the speed. With solid archives, it compresses
extremely well. How much difference depends on the material, I have a lot of
ISOs of PSP games, and using 7-Zip instead of RAR, I can usually expect a
quarter to a third of the archive size to be shaved off. That's amazing!