THE ULTIMATE NiBiTor "FANSPEED IC SETTINGS" GUIDE. Is your GPU to hot ? You don't want to use software to control the "Fan speed" . Well this could be the solution , put the Fan profile directly in to the BIOS and keep you GPU cool. WARNING: A BIOS FLASH IS NOT WITHOUT DANGER!!!!!!!!!!! You can use software to make fan speed profiles. Fan speed IC settings.(found in the "Temperatures Tab) Support for this function started with the 8800 (G92) series , when NVIDIA added the ADT7473 fan speed regulator. If you got one of these and up you can play around with this option. It is also possible that you got a 8800 (G92) and you just can adjust it , well time to update the BIOS , the first BIOS of the 8800 (G92) didn't have this support. Some vendors do not have full support in there BIOS for this "Thermal Fan Controller". It seems that a lot of 9800 (GT , GTX) are missing this control. I want to remind you that the Fan speed depend not only this "Thermal Fan Controller" , the BIOS and the driver still have some influence on the actual fan speed. First we start with introducing the "Thermal Fan Controller" ADT7473. The ADT7473 controller is a thermal monitor and multiple PWM fan controller for noise sensitive or power sensitive applications requiring active system cooling. It can drive a fan using either a low or high frequency drive signal, monitor the temperature of up to two remote sensor diodes plus its own internal temperature, and measure and control the speed of up to four fans so they operate at the lowest possible speed for minimum acoustic noise. The features that are interesting to us: - Dynamic TMIN control mode optimizes system acoustics intelligently. - Automatic fan speed control mode controls system cooling based on measured temperature. - Enhanced acoustic mode dramatically reduces user perception of changing fan speeds. - Thermal protection feature via THERM output. 1:Automatic speed Fan Control Overview (temperature increase = Fan speed increase). The ADT7473 can automatically control the speed of fans based on the measured temperature. This is done independently of CPU intervention once initial parameters are set up. (TCrit , TMin , min Duty cycle , TRange slope) Automatic fan speed control reduces acoustic noise by optimizing fan speed according to accurately measured temperature. Reducing fan speed can also decrease system current consumption. The automatic fan speed control mode is very flexible due to the number of programmable parameters, including "TMin" and "TRange slope". The "TMin" and "TRange slope" values for a temperature channel are critical because they define the thermal characteristics of the system. The thermal validation of the system is one of the most important steps in the design process, so these values should be selected carefully. Note that there is always a "Compensation" Value , it is seen in the Temperature Tab, it's often set at 6°C or 8°C by default , this has effect on all the temperature settings , example: 40°C "TMin" is actually 48°C with a "Compensation of 8°C , "TCrit" 90°C is actually 98°C and so on..... 1A: TMin Settings : (The temperature at which the fan turns at "min Duty cycle) "TMin" can be programmed in 1°C increments. Once the "TMin" value is exceeded, the fan will run faster than the "min Duty cycle". The fan turns back to "min Duty cycle" once the temperature drops below "TMin" − "THyst".(If "Thyst" has a value). 1B: "min Duty cycle" settings. "min Duty cycle" is the minimum duty cycle at which the fan in the GPU runs.(in %) For maximum system acoustic benefit the "min Duty cycle" should be set as low as possible. For better cooling it's recommended to start with 35%, 40%or even 45% "min Duty cycle". (For my GTX 280 it's set at 40%(quiet) with a lowered 2D voltage of 1.05v instead of the default 1.11v. Result: 43°C in idle). 1C: "TRange slope" settings ( Programs the "Fan Duty cycle" versus temperature control sloop) "TRange slope" is the range of temperature over which automatic fan control occurs once the programmed "TMin" temperature is exceeded. "TRange slope" is a temperature slope, not an arbitrary value. Example: a "TRange slope" of 40°C holds true only for "min Duty cycle" = 33%. If "min Duty cycle" is increased or decreased, the effective "TRange slope" changes. So in this case it takes 40°C for the Fan to go from "min Duty cycle" 33% to maximum Fan speed 100%. If you change the "min Duty cycle" to 50% the "TRange slope" still set to 40° it is no longer true 40°C but 30°C , so it takes 30°C to go from "min Duty cycle" 33% to maximum Fan speed 100%. (This you will notice when you set your wanted values for "TMin", "min Duty cycle", "TRange slope" in the info box at NiBiToR.) 1D:"TCrit" settings: (If the temperature is exceeds this critical limit , the fan will run at 100% for maximum cooling) "TCrit" is the absolute maximum temperature allowed on a temperature channel or in this case the GPU. When operating above this temperature, a component might be beyond its safe operating limit. When the temperature exceeds "TCrit" the Fan is driven at 100% duty cycle (full speed) to provide critical system cooling. The fans remain running at 100% until the temperature drops below "TCrit" −"THyst" (if "THyst" has a value). The default "THyst" value is 2°C or 0°C. The "TCrit" limit should be considered the maximum worst−case operating temperature of the system. Because exceeding "TCrit" limit the Fan runs at 100%, it has very negative acoustic effects. Ultimately, this limit should be set up as a fail−safe, and it should not be exceeded under normal system operating conditions. Note that the "TCrit" limit is nonmaskable and affect the fan speed no matter how the automatic fan control settings are configured. Example: "TCrit" = 75°C , "THyst" = 0°C , "TMin" = 40°C , "min Duty cycle" = 35% , "TRAnge slope" = 40°C. Normally the fan will hit 100% at 79°C (40°C + 40°C on a 35%) , but the "TCrit" is set at 75°C so when 75°C temperature is reached the Fan will run 100%. 1E: "THyst" settings. "THyst" is the amount of extra cooling a fan provides after the temperature has dropped back below "TMin" before the fan turns at "min Dut cycle". The premise for temperature hysteresis ("THyst") is that, without it, the fan would merely chatter or cycle on and off regularly whenever temperature is hovering at about the "TMin" setting. "THyst" values are programmable from 1°C to 15°C. "THyst" value of 0°C, disables hysteresis. In effect, this could cause the fan to cycle between normal speed and faster speed determent by the "Tmin" and "TRange slope", creating acoustic noise. Example: "TMin" = 50°C , "TCrit" = 80°C , "THyst" = 2°C. So when the temperature exceeds the "TMin" 50°C the fan will start running faster , but when the temperature drops below "TMin"50°C the fan will reach the "min Duty cycle" at 48°C caused by the 2°C "THyst". At passing 80°C "TCrit" the Fan will run 100%, and will slow down at 78°C , caused by the 2°C "THyst". "THyst" is only of importance if your GPU temperature stays around "TMin" or "TCrit" temperature. Most of the time it's set at 0°C by default at the GTX... series. Example: "Automatic speed" fan control. Now let's look at a example in "NiBiTor". You always need to remember that there is a "Compensation" value , I'm going to take 8° as "Compensation value and call it 8°Cc in my example.