SpeedFan supports both fixed manual speeds and automatic temperature-based fan control, but only when your motherboard exposes writable fan controls that SpeedFan understands. The program’s official download page lists SpeedFan 4.52 as the latest release and Windows support through Windows 10, not Windows 11: official SpeedFan download page. Treat it as legacy software for compatible desktop hardware, establish a BIOS/UEFI safety profile first, and verify every control against the physical fan it changes.
What SpeedFan’s control options mean
Manual or fixed control
Manual control sets a PWM or speed output directly—for example, 40%, 60%, or 100%. The value is not an RPM target: the actual speed depends on the fan, header circuitry, connector mode, splitter or hub, and firmware.
Automatic fan speed
The main-screen Automatic fan speed checkbox lets SpeedFan vary selected outputs in response to configured temperature sensors. It does not, by itself, make an unrecognized or firmware-locked header controllable.
Standard versus Advanced Fan Control
SpeedFan’s older control style is used when Advanced Fan Control is disabled. Enable it in Configure → Fan Control to use named controllers, temperature sources, curves, hysteresis, and output limits. The distinction matters because checking Automatic fan speed does not tell you which control engine is active. SpeedFan documents both methods at its Advanced Fan Control article.
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- Supports 6pcs 4 Pin PWM Fans (Fans not included, Not compatible with 3-pin/2-pin fans)
- Flexible Power Supply Input: Compatible with both SATA 12V and DC 5.5×2.5mm (5525) 12V input, allowing flexible power options
- Maximum total power output: 60W (5A@12V), with each port supporting up to 2A current while total combined current shall not exceed 5A
- Adjustable PWM duty cycle: 1%–99%
- Package include: a 4 Pin 12V PWM Fan Speed Controller ONLY
PWM output versus RPM feedback
A PWM or Speed entry is a control output. A Fan or RPM entry is feedback from a tachometer wire. They are not guaranteed to be paired: motherboard manufacturers choose how monitoring-chip pins are wired, and one output can drive several fans. A detected RPM reading therefore does not prove that SpeedFan can write to that fan’s control channel.
Check compatibility before changing a value
- Use a desktop motherboard with a supported hardware-monitoring chip and a controllable header.
- Confirm that the header is connected directly, through a suitable splitter, or through a controllable hub; a fixed-voltage or non-reporting hub may defeat software control.
- Identify whether each fan is 3-pin (normally voltage/DC controlled) or 4-pin (normally PWM controlled). Connector type is not a guarantee because header circuitry and BIOS mode still matter. Four-wire fans generally respond more linearly; three-wire fans can be less predictable.
- Treat laptops, all-in-ones, compact PCs, and many OEM desktops as poor candidates. Their embedded controllers and proprietary firmware may expose temperatures but not writable fan registers.
- Do not assume SpeedFan can control modern GPU fans. GPU drivers, VBIOS and vendor utilities commonly own those controls.
SpeedFan’s low-level access can cause problems on hardware that does not tolerate the writes. The official download page carries that warning: https://www.almico.com/sfdownload.php.
Prepare a safe fallback
- Enter BIOS/UEFI and create a sensible curve for the CPU and chassis headers. This remains the cooling policy when Windows or SpeedFan is not running.
- Record idle and sustained-load temperatures, current fan percentages, and RPM readings.
- Note each fan’s physical header, splitter or hub connection.
- Close other fan utilities, including motherboard and GPU control software, so two programs do not fight over one header.
Enable software or manual PWM control
- Start SpeedFan; administrative rights may be required on some systems.
- Open Configure, then the Advanced tab.
- Select the relevant hardware-monitoring chip in the chip list.
- Find entries such as PWM 1 mode, PWM 2 mode, or PWM 3 mode.
- Change only the relevant mode to Software controlled, Manual, or the equivalent option exposed by that chip. Labels vary; do not alter unrelated registers blindly.
- Apply the change, return to the main screen, and clear Automatic fan speed while testing fixed output.
If no software/manual mode exists, the chip may be read-only, the header may be firmware-controlled, or the detected channel may not correspond to a physical fan.
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- Compact, highly flexible controller for 4-pin PWM fans
- Works as a manual speed reducer or in tandem with the automatic motherboard fan control: achieve truly quiet operation, even with high-speed PWM fans such as Noctua’s industrialPPC series
- “No stop” mode: prevents the fan from falling below a speed of 300rpm in order to avoid BIOS fan errors
- Includes a 3-way splitter cable for controlling up to 3 fans simultaneously
- 6-year manufacturer’s warranty
Map each PWM control to a physical fan
Never infer that PWM1 is the CPU fan or that Fan1 matches PWM1. Use a controlled test:
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- Record current percentages, RPM values, temperatures, and audible fan behavior.
- Disable automatic control and set a conservative, relatively high value.
- Change one PWM or Speed value at a time.
- Wait briefly, then observe RPM, sound, and temperature. A change in one RPM reading may identify the connected fan; a temperature change alone is not proof.
- Restore the previous safe value before testing the next channel.
- Write down the result, such as
PWM1 → CPU fan,PWM2 → rear fan, orPWM3 → several case fans.
SpeedFan’s documentation explicitly describes this trial-and-error mapping because manufacturers do not use a universal numbering scheme: https://www.almico.com/sfarticle.php?id=5.
Set a fixed manual speed safely
- Start at a high value rather than testing 0%.
- Lower the output in small steps until the fan reaches the lowest speed at which it starts reliably and continues spinning.
- Set the normal minimum above that threshold. Startup voltage can be higher than the voltage needed to keep a spinning fan running.
- Use 100% when checking cooling capacity or responding to a temperature problem. SpeedFan’s guidance treats 100% as a general maximum, while allowing a lower maximum when noise is excessive.
- Test idle, ordinary use, and sustained workload while watching temperatures. A percentage is not a universal cooling or noise measurement.
Do not use an experimentally low value as a permanent setting, and never stop a CPU or GPU fan without a verified thermal strategy. A configured warning temperature can force the relevant PWM to 100%, regardless of the selected maximum, according to SpeedFan’s documentation at https://www.almico.com/speedfan.php/sfdownload.php.
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- MAX OUT YOUR FAN SETUP: Enjoy independent control for every fan, moving beyond limited hub signals for customization.
- POWER YOUR BULD: Supplies up to 2 A per port and a total maximum current of 4.5 A, unlike motherboards where different ports may provide varying output levels.
- PLUG & PLAY SUPPORT: Native driver support for both Windows and Linux (Kernel 7.2+) enables compatibility with a wide range of fan‑control and monitoring software.
- ZERO CABLE CHAOS: Centralized cable management through a fan controller ensures a cleaner build by eliminating the need for extensions and Y-splitter cables.
Configure automatic temperature control
- In Configure → Temperatures, identify genuine CPU, motherboard, GPU, storage, and other relevant sensors. Disable duplicate, unused, or implausible entries.
- In Configure → Fans, retain only genuine RPM readings.
- In Configure → Speeds, identify usable PWM channels and set conservative minimum and maximum values.
- In Configure → Temperatures, associate each temperature with the fan or fans it should influence.
- Return to the main screen and enable Automatic fan speed.
- Test at idle, during normal use, and under sustained load. Confirm that the mapped physical fan responds and that temperatures remain acceptable.
Several temperature sources may influence one output, and one fan can change more than one temperature. A temperature label therefore does not prove that the fan is physically connected to that sensor.
Build an Advanced Fan Control curve
In Configure → Fan Control, create a controller and specify:
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- Fan controller: the named strategy.
- Controlled Speed: the PWM output to change.
- Source temperatures: one or more sensors driving that output.
- Curve points: requested PWM percentages at selected temperatures.
- Minimum and maximum temperatures: the lower and upper curve bounds. Below the minimum, the minimum-point speed is used; above the maximum, the maximum-point speed is used.
- MAX method: uses the highest requested speed among selected sources.
- SUM method: combines requests according to the selected strategy.
- Hysteresis: delays downward changes until temperature falls sufficiently, reducing rapid oscillation.
- Minimum and maximum PWM: clamps the final output.
- Warning temperature: triggers 100% output for the relevant PWM when exceeded.
Use a curve with a real startup margin, a gradual increase through normal temperatures, and a high-temperature point that provides adequate cooling. Keep the number of competing sensors small enough that you can understand why the output changes.
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- Supports 6pcs 4 Pin PWM Fans (Fans not included, Not compatible with 3-pin/2-pin fans)
- Flexible Power Supply Input: Compatible with both Type-C 12V (Supports QC3.0 / PD3.0) and DC 5.5×2.1mm (5521) 12V input, allowing flexible power options
- Maximum total power output: 60W (5A@12V), with each port supporting up to 2A current while total combined current shall not exceed 5A
- Adjustable PWM duty cycle: 10 lights represent PWM duty cycle (0-100% in 10% increments), the color of indicator light shows input voltage status. ( Blue light: 12V input normal. Orange light: Input voltage below 11.8V, fan operates at low speed. Red light: Input voltage below 8.4V, your power device unusable.)
- Package include: a 4 Pin 12V PWM Fan Speed Controller ONLY
Troubleshoot common failures
The PWM value changes but the fan does not
- You selected the wrong PWM channel.
- The header remains under BIOS or vendor control.
- The fan is on a fixed-voltage header or an unsuitable hub.
- The header is in DC mode when PWM is required, or the reverse.
- The chip is detectable but not writable.
- The fan is below its startup threshold, or the displayed reading is stale.
Restore a high safe value, check the physical wiring and BIOS mode, test channels one at a time, and stop using SpeedFan if fan behavior or temperature becomes uncertain.
The fan stops at a low percentage
This usually indicates a startup or sustaining-voltage limit. Raise the minimum above the point where the fan stalls or fails to restart.
Fans repeatedly speed up and slow down
Increase hysteresis or widen the temperature gap, remove competing sensor inputs, and check that BIOS and SpeedFan are not both controlling the header. An unstable low-speed range can also cause cycling.
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- 5V Input: The Input of the product is TYPE-C female port, can be perfectly compatible with TYPE-C port charger as a power supply device, It is recommended to use a power adapter that provides 5V output 🔺Note: charger power must exceed fan's total power for full speed.
- 12V Output: The Output is a 4 Pin socket for 12V PWM fan (🔺Not compatible with 3-pin/2-pin fans), built-in DC-DC boost circuit, 5V boost to 12V, speed regulation is achieved by outputting PWM signals. Maximum output power is determined by your charger's 5V output capability.
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Settings disappear after reboot
Startup configuration and administrative permissions may be required. Test after reboot, but retain a BIOS/UEFI curve that is safe when SpeedFan is not running; startup automation is not a substitute for firmware protection.
Temperatures look wrong
Compare questionable readings with BIOS/UEFI or a trusted manufacturer utility. Do not base a curve on a duplicate, unused, or obviously implausible sensor.
The system becomes unstable
Disable automatic control, exit SpeedFan, restore BIOS or manufacturer fan settings, and uninstall SpeedFan if instability persists. Its official warning about low-level hardware access is at https://www.almico.com/sfdownload.php.
Should you still use SpeedFan?
| Situation | Best choice | Reason |
|---|---|---|
| Older compatible desktop motherboard; channels map correctly | SpeedFan can be suitable | Manual and automatic control are available when the chip and wiring are writable. |
| Need cooling before Windows starts or during software failure | BIOS/UEFI | Firmware control persists independently of Windows. |
| Modern Windows system needing curves, calibration and hysteresis | Fan Control | Its documentation covers manual control, calibration, curves, response time, start/stop thresholds, limits and plugins: official documentation. |
| Branded laptop, OEM desktop or motherboard ecosystem | Manufacturer utility | Embedded-controller and proprietary controls are more likely to be supported. |
| Simple physical speed adjustment only | Hardware controller such as Noctua NA-FC1 | Useful for manual adjustment, but it cannot create sensor-driven motherboard curves: official product page. |
Fan Control is not universal either. Its documentation notes hardware-specific restrictions, including minimum command percentages and zero-RPM limitations on some modern NVIDIA and AMD GPUs. Do not run multiple fan-control utilities simultaneously.
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Quick-reference checklist
- Establish and test a BIOS/UEFI fallback curve.
- Confirm SpeedFan detects the relevant chip and writable controls.
- Place the correct PWM mode under software control.
- Map each PWM output to a physical fan instead of trusting labels.
- Find the lowest reliable startup speed and keep a safety margin.
- Configure real sensors, fans and speed channels only.
- Choose standard or Advanced Fan Control deliberately.
- Test idle, normal use, sustained load and reboot behavior.
- Rollback to BIOS/UEFI control if temperatures, RPMs or stability become uncertain.
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