PC Fan Curve Calculator for CPU, GPU and Case Fans

Where to Enter Your Curve

Noctua recommends setting 4-pin PWM fans in the BIOS when you can, since that avoids software problems. Pick PWM for the fan header rather than Auto, which Noctua says doesn't always detect PWM fans.

Where	Points	Look for
ASUS BIOS	4 on boards like the ROG Strix X670E	Monitor, then Q-Fan Configuration
MSI BIOS	4	Smart Fan Mode
Gigabyte BIOS	Up to 7	Smart Fan 6
Fan Control app	As many as you like	A fan curve linked to a temperature sensor
MSI Afterburner, for graphics cards	As many as you like	Settings, then Fan

If your BIOS has a fan tuning test, Noctua suggests running it before you set a curve.

How Each Point Is Picked

The fans hold a low, steady speed while your PC idles. Once the temperature passes the ramp point, they climb along a gentle bend and reach full speed a few degrees under the chip's rated maximum.

Setting	Quiet	Balanced	Cool
Full speed	5 °C under the max	10 °C under	15 °C under
Ramp starts	55 °C	50 °C	45 °C
Ramp with your idle temp	15 °C above it	12 °C above	10 °C above
Lowest speed: CPU, case, GPU	20, 20, 30%	30, 25, 35%	40, 35, 40%

The points are spread evenly over the climb, so the straight lines your BIOS draws between them follow the bend. The speed never drops below your fan's lowest RPM, which Intel's PWM fan spec says must be 30% of top speed or less.

AIO curves follow the liquid instead, which moves over a much smaller range. Balanced starts climbing at 33 °C and reaches full speed at 42 °C, close to Corsair's example curve that tops out at 45 °C.

Why Full Speed Waits for the Last Few Degrees

Modern processors are built to run hot. Intel says reaching the maximum under a heavy load isn't necessarily a problem, and its limits usually fall between 100 and 110 °C.

AMD chips work the same way. Tom's Hardware found Ryzen 7000 chips regularly reach 90 to 95 °C under load, which is within spec.

Graphics cards have lower limits. NVIDIA lists a maximum GPU temperature of 90 °C for the RTX 4070 family and 85 to 88 °C for the RTX 5070 cards.

AMD has said up to 110 °C junction temperature is expected while gaming on its RX 5700 cards. Radeon owners can pick Other graphics card and enter the limit for the sensor their curve follows.

Noctua agrees that any temperature under the rated maximum is safe. Faster fans before that point mostly buy you noise.

What a Good Fan Curve Looks Like

A good curve stays flat and quiet at idle, then rises steadily under load. Noctua warns that default curves are often too steep, with high fan speeds at low temperatures.

Noctua also notes that a changing fan speed can be more distracting than a steady one. For a quiet PC, it suggests case fans at 20% until the CPU reaches 60 °C, with CPU fans about 10% higher.

Short spikes are the other problem. Noctua's own Fan Control profiles use 5 °C or 5 seconds of hysteresis, so the fans ignore spikes that last only a few seconds.

Your software may use another name for it. Fan Control calls it hysteresis and response time, ASUS Fan Xpert uses acceleration and deceleration time, and Gigabyte offers a temperature interval.

Which Temperature Your Fans Should Follow

CPU cooler fans follow the CPU, and graphics card fans follow the GPU. Case fans can follow either one.

Noctua's profiles let whichever part is hotter set the speed. Fan Control's Mix curve does this with its Max setting, and ASUS Fan Xpert can follow the hottest of up to three sources.

AIO radiator fans work best on the liquid temperature. Corsair explains that the coolant, not the fan speed, sets how cool the CPU stays, and fans that follow the CPU spin up for no reason.

Can't read the liquid sensor? Pick CPU temperature for the AIO and add a few seconds of hysteresis.

Letting Fans Stop When Cool

Not every fan can stop. Intel's PWM spec allows fans that hold their lowest speed at any low setting, as well as fans that switch off at 0%.

Check your fan's spec sheet before you count on it. Noctua's current fans list 0 RPM at 0% PWM, and ARCTIC's PST fans stop below 5%.

Graphics cards often stop their fans on their own. ASUS cards stop below about 50 °C at low power, and MSI cards below 60 °C.

Under software control, NVIDIA cards hold at least 30%, as the Fan Control docs note. If the fans keep starting and stopping, MSI suggests turning on Override zero fan speed with hardware curve in Afterburner.

Fan Speed, Airflow and Noise

Pick your fan above to see its RPM, airflow and noise at each point. Airflow rises in step with speed, since Greenheck's fan basics state that CFM varies directly with RPM.

Noise falls much faster than airflow. Fan sound changes by 50 times the log of the speed change, as Punker's acoustics guide shows, so half speed is about 15 dB quieter with half the airflow.

Treat these numbers as estimates. Intel's PWM spec only asks a fan's real speed to land within 10% of its setting.

Check the Airflow Too

Speeds are only half the job. Compare your intake and exhaust totals with the PC airflow calculator, then watch where the air goes in the 3D airflow simulator.

For fan placement, read our guide to improving case airflow and which way top fans should blow. Building in a Lian Li O11? Our O11 fan guide maps every mount.