Can't "Stop" my CPU Fan ?

[Merrattic]

OK, before you all go, why would you want to, this is about getting full control over my fans on my new system. I have got so far with it but this last bit is niggling me.

Specs

Asus Z87M PLUS motherboard (with Q Fan Control)
Intel i5 4670K processor
CPU Cooler: TITAN TTC-NK35TZ/RPW/V3 (http://www.titan-cd.com/product_imag...sal/35v2_1.jpg)
Nvidia GTX 650
4gb ram
128gb SSD

Xubuntu 12.04.3
sensors detected: coretemp nct6775


lm-sensors installed, pwmconfig run and fancontrol in place with a config file

# Configuration file generated by pwmconfig, changes will be lost
# FAN1 is Chassis Fan  #  FAN2 is CPU Fan

INTERVAL=10
DEVPATH=hwmon0= hwmon2=devices/platform/nct6775.656
DEVNAME=hwmon0=acpitz hwmon2=nct6791
FCTEMPS=hwmon2/device/pwm1=hwmon0/temp1_input hwmon2/device/pwm2=hwmon0/temp2_input
#                CHASSIS FAN                                                    CPU FAN
FCFANS=hwmon2/device/pwm1=hwmon2/device/fan1_input hwmon2/device/pwm2=hwmon2/device/fan2_input
#             CHASSIS                            CPU
MINTEMP=hwmon2/device/pwm1=35 hwmon2/device/pwm2=35
MAXTEMP=hwmon2/device/pwm1=80 hwmon2/device/pwm2=70
MINSTART=hwmon2/device/pwm1=90 hwmon2/device/pwm2=50
MINSTOP=hwmon2/device/pwm1=59 hwmon2/device/pwm2=10

After disabling fancontrol (gets noisy!) I have been sending pwm changes to each of the fans like so

echo 100 > /sys/class/hwmon/hwmon2/device/pwm2

using values to echo between 0 and 255. For the case fan (3 pin!), I found the fan would stop at 59 and restart at 90, so set those values. Nice and quiet

However I can put 0 in for the CPU fan (4 pin) and the fan speed will only drop to @ 1300 rpm (top speed = 2700rpm), it won't stop as it should.

CPU at idle is only @ 29 degrees C.

I have been into the bios and set up the CPU fan as manual with a temp range of 40 and 70 degrees for testing

My target is to reduce the CPU fan speed to @ 750rpm at idle and have the case fan running slowly all the time.


I must be missing something......