Antec NSK 1380

[Jim]

I built a "samall" system using the Antec NSK 1380 and Gigabyte GA-
MA69GM-S2H motherboard. Over the last few days, its been running
continuously and I've been watching the system and CPU temps and fan
speeds using the BIOS health utility. System temp has gone from 30C
to a high of 43 while CPU temp has gone from 30C to 41C. CPU fan
started out at 1800rpm and gone up to 2250 while the system fan has
stayed constant at 980 rpm. Here's my question - the Antec case and
PSU has a fan connection which I have connected to the MB system fan
SYS_FAN header and I expected the fan speed to increase with system
temp. Any reason why not?

 

[Paul]

I built a "samall" system using the Antec NSK 1380 and Gigabyte GA-
MA69GM-S2H motherboard. Over the last few days, its been running
continuously and I've been watching the system and CPU temps and fan
speeds using the BIOS health utility. System temp has gone from 30C
to a high of 43 while CPU temp has gone from 30C to 41C. CPU fan
started out at 1800rpm and gone up to 2250 while the system fan has
stayed constant at 980 rpm. Here's my question - the Antec case and
PSU has a fan connection which I have connected to the MB system fan
SYS_FAN header and I expected the fan speed to increase with system
temp. Any reason why not?

This picture is from the NSK 1380 entry on Newegg. The blue/black
wire pair, with three pin connector on the end, is for "fan monitoring"
of the PSU fan speed. It does not control the PSU fan.

http://c1.neweggimages.com/NeweggImage/productimage/11-129-038-15.jpg

It appears the NSK 1380 has a 120mm fan on the back, for chassis cooling.
Your motherboard would either need a BIOS feature, for fan control,
or you'd need to use a program like Speedfan (almico.com) to play
with the fan speed.

Typically, a motherboard has a Super I/O chip, which may incorporate
a hardware monitor interface. There can be three to five fan interfaces
included. The fans have an RPM measurement circuit, that works from
pulses detected on the third wire from the fan.

To control the fan speed, the motherboard needs a transistor as a buffer
from the hardware monitor. The transistor allows the fan voltage to be
adjusted. (Some CPU fans now have a fourth wire, and the control method
on those is a bit different - it uses a PWM logic signal, to tell the
CPU fan how fast to run.) In any case, just because you install Speedfan
and "turn the knob" in Speedfan, does not guarantee that the motherboard
possesses fan speed control. The motherboard maker has to include the
transistor, located near the fan header, if they intended you to have
control over the speed. Speedfan has no way of detecting (in the
enumeration sense), whether a transistor is near the header or not.

The best computers for this, are prebuilt ones, like from Dell or HP.
Some of those have a transistor for every header, and all are under
control for best noise performance. On Asus motherboards, a user can
guess at the presence of transistors, based on whether "QFAN" or "QFAN2"
is used as a descriptive term. QFAN only controls the CPU fan, while
QFAN2 controls the CPU fan, plus the system fan header.

Looking at the manual for your motherboard, the first problem is there
are only two fan headers. The second problem, is the BIOS only shows
"CPU Smart Fan", implying on the CPU header has a transistor (or uses
the fourth, PWM logic signal, to do the job).

The best you can do (and you'll still need to test this) is:

1) Connect CPU fan to CPU fan header. Enable "CPU Smart Fan" if you
desire the Super I/O chip to automatically control the fan. If the
fan on the CPU heatsink is a small four pin connector type, then you
can select "PWM" as the control method in the BIOS.

2) Connect the NSK 1380 fan to the SYS_FAN motherboard header. Use
Speedfan to see if there is any possibility of control. If the
fan speed doesn't change, then no transistor is present on the
motherboard.

3) Leave the blue/black two wire monitor cable from the PSU disconnected.
If your motherboard had three fan headers, you could connect it, and
be able to monitor the PSU fan speed. But since your motherboard only
appears to have two headers, then the PSU cable will have to remain
disconnected.

You can always use a 4 pin Molex disk drive, to three pin fan adapter,
to power the rear 120mm fan. Or use a "rheobus" tray mounted speed
controller, to make manual adjustments to the rear fan speed. There
are also products you can buy, for automated fan control, which
don't rely on the motherboard. They would come with their own
temperature sensor, such as a sensor that measures case temperature.

HTH,
Paul

 

[Jim]

This picture is from the NSK 1380 entry on Newegg. The blue/black
wire pair, with three pin connector on the end, is for "fan monitoring"
of the PSU fan speed. It does not control the PSU fan.

http://c1.neweggimages.com/NeweggImage/productimage/11-129-038-15.jpg

It appears the NSK 1380 has a 120mm fan on the back, for chassis cooling.
Your motherboard would either need a BIOS feature, for fan control,
or you'd need to use a program like Speedfan (almico.com) to play
with the fan speed.

Typically, a motherboard has a Super I/O chip, which may incorporate
a hardware monitor interface. There can be three to five fan interfaces
included. The fans have an RPM measurement circuit, that works from
pulses detected on the third wire from the fan.

To control the fan speed, the motherboard needs a transistor as a buffer
from the hardware monitor. The transistor allows the fan voltage to be
adjusted. (Some CPU fans now have a fourth wire, and the control method
on those is a bit different - it uses a PWM logic signal, to tell the
CPU fan how fast to run.) In any case, just because you install Speedfan
and "turn the knob" in Speedfan, does not guarantee that the motherboard
possesses fan speed control. The motherboard maker has to include the
transistor, located near the fan header, if they intended you to have
control over the speed. Speedfan has no way of detecting (in the
enumeration sense), whether a transistor is near the header or not.

The best computers for this, are prebuilt ones, like from Dell or HP.
Some of those have a transistor for every header, and all are under
control for best noise performance. On Asus motherboards, a user can
guess at the presence of transistors, based on whether "QFAN" or "QFAN2"
is used as a descriptive term. QFAN only controls the CPU fan, while
QFAN2 controls the CPU fan, plus the system fan header.

Looking at the manual for your motherboard, the first problem is there
are only two fan headers. The second problem, is the BIOS only shows
"CPU Smart Fan", implying on the CPU header has a transistor (or uses
the fourth, PWM logic signal, to do the job).

The best you can do (and you'll still need to test this) is:

1) Connect CPU fan to CPU fan header. Enable "CPU Smart Fan" if you
    desire the Super I/O chip to automatically control the fan. If the
    fan on the CPU heatsink is a small four pin connector type, then you
    can select "PWM" as the control method in the BIOS.

2) Connect the NSK 1380 fan to the SYS_FAN motherboard header. Use
    Speedfan to see if there is any possibility of control. If the
    fan speed doesn't change, then no transistor is present on the
    motherboard.

3) Leave the blue/black two wire monitor cable from the PSU disconnected.
    If your motherboard had three fan headers, you could connect it, and
    be able to monitor the PSU fan speed. But since your motherboard only
    appears to have two headers, then the PSU cable will have to remain
    disconnected.

You can always use a 4 pin Molex disk drive, to three pin fan adapter,
to power the rear 120mm fan. Or use a "rheobus" tray mounted speed
controller, to make manual adjustments to the rear fan speed. There
are also products you can buy, for automated fan control, which
don't rely on the motherboard. They would come with their own
temperature sensor, such as a sensor that measures case temperature.

HTH,
      Paul

Thanks, Paul. You have clarified a number of things for me. My main
mistake was assuming the fan wires from the PSU were control wires. I
may as well disconnect them in that case from the SYS_FAN header and
attach another fan to that. My concern is that once a hard drive is
added as well as an optical drive, there will be inadequate cooling
mostly because everything is packed so closely together.

 

[Jim]

Thanks, Paul. You have clarified a number of things for me.  My main
mistake was assuming the fan wires from the PSU were control wires.  I
may as well disconnect them in that case from the SYS_FAN header and
attach another fan to that.  My concern is that once a hard drive is
added as well as an optical drive, there will be inadequate cooling
mostly because everything is packed so closely together.

Made another discovery last night. Packed with the Antec case was a
slot mountable fan driven by a regular power connector (no sensors or
other controls). When mounted it provides a pretty strong airflow
across the case. Makes me wonder if Antec knows there is a cooling
problem with this case.

 

[Jim]

Made another discovery last night.  Packed with the Antec case was a
slot mountable fan driven by a regular power connector (no sensors or
other controls).  When mounted it provides a pretty strong airflow
across the case.  Makes me wonder if Antec knows there is a cooling
problem with this case.

I finally got this all figured out. This case is very tight when all
closed up. If the hard drive is mounted in the "default" position
(horizontally in the centre), it is vey close to the CPU fan. In this
position, it is very easy for the hard drive cable or power connector
to rub against the CPU fan housing and even the fan blades
themselves. When all is assembled, it is very difficult to observe
that the CPU fan is stopped. This is what happened to me.

 

[John Doe]

When all is assembled, it is very difficult to observe that the
CPU fan is stopped. This is what happened to me.

In my opinion, that's about the only time you really need to have a
look inside the case while the system is powered up, to make sure
the fans are running. I do that check every time the system is
powered up after messing around inside of the case.