Fan Control Documentation

Curves and manual control

Each control card represents one fan header or pump and can run either at a fixed value you set by hand or by following a fan curve. Open the "curve" dropdown on the card to attach a curve. Prefer a fixed value? Tick "Manual control" in the card’s menu and drag the slider.

Speed sensor pairing

Before a control can be tuned it needs to know which RPM sensor reports its speed. Pairing links the two so the app can see how the fan actually responds, and it is a prerequisite for calibration. Pick the sensor yourself from the dropdown, or run the pairing assistant and let it match headers to tachometer readings automatically.

Calibration

NVIDIA

Recent NVIDIA cards, including the RTX lines, put a few restrictions on fan control from outside their own driver. The ones that matter most:

• Minimum %: The lowest accepted command is about 30%, and a manual 0 RPM request is rejected.
• 0 RPM minimum temperature: The card only allows its fans to stop below a firmware threshold, typically near 45 °C.
• 0 RPM maximum power draw: Driving several monitors can push idle power above the limit at which the fans are allowed to stop.

Fan Control works around this by handing control back to the driver whenever the curve asks for 0%. A card with a native fan-stop feature can then idle silently, but whether it does depends on the conditions above being met.

A practical GPU graph therefore keeps 0% at or below the card’s fan-stop temperature, jumps straight to roughly 30% above it, and rises from there however you like.

AMD

Current AMD Radeon cards are normally managed through the Adrenalin software, and Fan Control talks to the same ADLX interface to read temperatures, fan RPM and to set fan speed. Reading sensors is free of side effects; actually taking over the fan comes with these caveats:

• Overclocking reset: Sending a fan command clears any custom tuning profile you had applied in Adrenalin.
• Zero RPM: The card enforces its own temperature below which the fans may stop, shown as a dotted line in Adrenalin’s fan chart. Build your curve around that point rather than fighting it.
• Minimum %: Apart from a true 0% (see Zero RPM), the lowest accepted command is usually 30%; anything under it is ignored and the card stays at its floor.

So a sensible Radeon graph places 0% at or below the zero-RPM temperature, steps directly to the card’s minimum percentage above it, and climbs from there to suit your noise tolerance.

RPM mode

Every curve type can switch to RPM mode from its menu. In that mode the curve produces a target rotation speed instead of a percentage. Because the app needs to know how percent maps to RPM, only controls that have completed calibration can use it.

Linear

Linear draws a straight line between two temperature points and two fan speeds, then follows one temperature source along it.

Under the minimum temperature the fan holds the minimum speed.

Over the maximum temperature the fan holds the maximum speed.

Graph

Graph lets you shape any response you want by placing points on a temperature-versus-speed chart.

Click "Edit" to open the editor: left-click adds a point, right-click deletes one, and hovering a point exposes the "Selected Point" fields for exact values.

Mix Fan Curve

Mix merges two or more existing curves into one output using a function such as Max or Average, so a single fan can respond to several components at once.

Trigger

Trigger behaves like a thermostat with two thresholds. It stays at the idle speed until the sensor climbs past the load temperature, then holds the load speed until the sensor falls back below the idle temperature. Nothing changes in between, which avoids constant ramping.

Flat

Flat outputs one constant percentage. Assign it to several controls and you can change them all from a single place.

Sync

Sync mirrors whatever percentage another control is currently outputting. Point several fans at one master control and they follow it, including any curve you later assign to that master.

Auto

Auto hunts for the quietest fan speed that still holds a target load temperature. It shines under steady loads such as rendering or long gaming sessions and is less useful for bursty desktop work. The curve splits temperatures into two zones. Up to the load temperature it acts like a plain linear curve. Inside the load zone, bounded by the Load Temperature and Deadband settings, a feedback loop watches which way the temperature is trending and nudges the speed up or down. When the reading keeps drifting downward, the speed is trimmed step by step until the temperature stabilizes, which is the lowest speed that can sustain the target.

Time Average

Time Average smooths a chosen sensor by reporting its rolling average over a window you define, which keeps brief spikes from ramping fans.

Mix Sensor

Mix Sensor combines several temperature readings into one virtual sensor by running a function across them.

File

File reads a temperature from a text file on disk. Write the value in Celsius as the first line of a ".sensor" file and the app treats it like any other sensor, which is a simple bridge for hardware or scripts the software cannot poll on its own.

Offset

Offset creates a copy of an existing sensor shifted up or down by a fixed amount or a percentage.

-c --config

-w --window

-m --minimized

-r --refresh

-e --exit

-sc --service-client