Profiles and curves in Smart Fan 5 for optimal airflow

Properly adjusting the fans on a Gigabyte motherboard with SmartFan 5 It can make the difference between a noisy PC constantly spiking and a cool, quiet machine that's barely noticeable. Many people start by linking all their fans to the CPU temperature and end up with a constant "spinning up and down" effect: any small temperature spike causes the fans to react abruptly, which is very annoying.

The idea behind this article is that you can leave your fans with a optimized airflow, controlled noise, and curves of logic fanUsing Smart Fan 5 profiles and options (and, if you want, external programs) without going crazy with terms like PWM, DC, hysteresis, sensors or percentages that you don't really know what real RPM they correspond to.

What is a fan curve and why does it matter so much?

When we talk about the fan curve, we are referring to the relationship between the temperature of a sensor and the fan speedThis curve, usually expressed as a percentage of PWM or voltage, defines when the fan is running slowly, when it's accelerating, and when it's at maximum speed.

A well-designed curve allows you Keep the fans very low at idle.Increase them gradually as the temperature rises and reserve 100% only for when the system truly needs it. If the curve is poorly designed, you'll have sudden noise spikes, insufficient cooling or fans speeding up and slowing down every few seconds.

The default profiles in many BIOSes (including Gigabyte's) are often very generic: sometimes they're too conservative with temperatures or too aggressive with noise. That's why it's useful to know how to create a custom BIOS profile. Custom curve tailored to your case, your fans, and your PC usage.

Basic concepts of fan control: PWM, DC and sensors

Control Types: PWM vs DC

On a modern motherboard like the Aorus with Smart Fan 5, you can find two main ways to control a fan: PWM (pulse width modulation) y DC (voltage control)Understanding the difference is key to avoiding mistakes when configuring the printheads.

A fan 4-pin PWM uses a digital signal The fourth pin tells the motor what percentage of time it should be powered, allowing for very fine and stable RPM control, especially at low speeds. This results in very smooth power curves, very low minimum speeds, and, in some models, even 0 RPM mode real when the percentage is 0%.

A fan 3 pins operates in DC modeIn other words, the motherboard modifies the voltage supplied to the fan. This also allows for speed changes, but less precisely and with a higher minimum RPM limit. Furthermore, some 3-pin fans barely drop below a certain threshold before stopping.

In Smart Fan 5 you can specify for each header whether you want to use mode PWM or DCIt's important that a PWM fan is connected to a header configured for PWM, and that a 3-pin fan normally uses DC control. Mixing the wrong modes can cause problems. unstable readings, fans that won't start or strange noises.

Where do the temperatures come from: available sensors

Another critical point is the temperature at which you'll assign each fan. Current Gigabyte motherboards allow you to associate each fan curve with different temperatures. temperature sources:

• CPU package temperature, ideal for the CPU fan curve or an AIO radiator.
• Motherboard or VRM temperatures, useful for controlling fans that help cool the power supply area.
• Ambient temperature of the box, sometimes measured by an internal sensor that better reflects the overall heat inside the chassis.
• GPU temperature If the external software allows it, it's very interesting for synchronizing the case fans with the graphics card when you're gaming.

Choosing the right sensor is key because It doesn't make sense for all the fans to respond only to the CPU.For example, front and rear fans usually work best if they are guided by the temperature of the case or the GPU, since these are what determine the overall heat while gaming.

Airflow: how many fans and where to place them

Before you start drawing curves, it's a good idea to check if your box has a minimally decent ventilation schemeHowever fine the curve is, if the airflow is poor, the temperatures will still be high.

Ideally, one should maintain a positive pressure in the box: that there is slightly more air entering than exiting. This helps ensure that dust enters primarily through the filters, as the airflow is more organized. For this purpose, the following is typically installed:

• 2 or 3 front intake fans, preferably 140 mm and with a good flow rate (about 1500 RPM maximum is more than enough).
• 1 rear exhaust fan, with around 1200 RPM is usually enough to accompany the front lights.
• 1 or 2 top exhaust fans, which take advantage of the fact that hot air tends to rise.

As a general rule, fans Front and rear are the most important For the overall flow, these are the ones that make the most sense to follow a temperature-related curve. The upper ones often work well at a relatively constant speed, since hot air rises and they don't require a tremendous effort to evacuate it.

When setting RPM, a very reasonable approach is to use Frontal winds at maximum speed around 60-65 ºCleaving them at a minimum of around 20°C. The rear can be a bit more relaxed, for example with a maximum slightly lower if it's a lower RPM. The upper ones are often left fixed between 60% and 75% of its speed, provided that the noise is not annoying.

Access Smart Fan 5 and other controls from the BIOS

To adjust the curves on a Gigabyte Aorus motherboard, you need to enter the BIOS/UEFI and locate the section for Smart Fan 5 or Monitor of hardware, where the CPU_FAN, SYS_FAN, PUMP, etc. headers are displayed.

The general steps for any modern motherboard are very similar: Turn off your PC, hold down the DEL or F2 key and turn on the equipment so that Boot in BIOS. If you're having trouble pressing the right key, in Windows 10/11 You can access the firmware from the advanced startup options without having to sync the keyboard.

Once in BIOS, in Gigabyte's advanced menu you will see a graphical window with the detected fans, their current RPM, and a graph with the temperature curve versus percentage of speedFrom there you can select each fan and choose whether it is controlled in PWM or DC mode, as well as the reference sensor.

Predefined profiles versus manual mode

Smart Fan 5 typically offers several automatic profiles, such as Normal, Silent, Performance or similar. These profiles shift the curve in a generic way: silent mode delays the RPM increase and prioritizes noise, while the default or performance profiles accelerate sooner to maintain somewhat lower temperatures.

These profiles are a good starting point if you don't want to complicate things, but if you really want your PC to perform well behaves exactly as you want, the thing to do is switch to mode Manual and position the curve points as you like. In that view, you can adjust each temperature/percentage marker for each connected fan.

Keep in mind that many users complain that the BIOS is clumsy at experimenting with curvesBecause each change requires restarting and testing in Windows, going back to the BIOS, etc. If you want to go faster, later we'll look at software tools that work on top of what the motherboard does and allow you to fine-tune without so many restarts.

Switch from PWM percentage to RPM logic

One of the things that confuses people most about Smart Fan 5 is that the interface asks you to define the speed as PWM percentage (for example, 50% or 100%) instead of allowing you to directly set specific RPMs. This makes it more difficult to find the exact point where the fan sounds good or becomes annoying.

The key is to do a small fan pre-calibrationYou can do it from the BIOS itself, where there is often an auto-adjustment option, or simply by writing it down:

• Which is the Minimum RPM at which the fan starts and remains stable (usually 20-30% of PWM).
• What RPM does it reach at 50% PWM and 100%, giving you a mental chart to know that, for example, your fan goes from 500 RPM to 1500 RPM.

With that information, you can now make the following associations in your mind: 30% = X RPM, 50% = Y RPM, 100% = Z RPMAlthough Smart Fan 5 doesn't let you directly set the RPM, you'll have a general idea of ​​what zone you're in when you move each point on the curve.

If your fans have a range where they make a particularly unpleasant noise At certain low RPMs, you can avoid that specific range by not using the corresponding percentages. For example, if they sound strange at 600-800 RPM but sound good at 500-1000, you can design a curve that passes through that area faster or skips it altogether.

How to create a solid fan curve step by step

1. Calibrate minimum and maximum limits

Before drawing anything, it is advisable to determine precisely reliable minimum and maximum RPMs of each fan. To do this you can:

• Use the BIOS's own adjustment tools (Smart Fan 5, Q-Fan on ASUS, hardware monitor on MSI, etc.) to gradually lower the percentage until the fan safely stops spinning.
• Use software such as FanControl, Argus Monitor or SpeedFan in Windows to perform percentage sweeps and see in real time the RPM that each fan obtains.
• Note what percentage of PWM is equivalent to the minimum stable speed and which at a reasonable maximum speed where the noise is already high but acceptable.

This step prevents you from setting the speed too low, which would cause the fan to stop (or start and stop repeatedly), and ensures that the curve always maintains a continuous air flow.

2. Define consistent temperature steps

A good curve usually has several Key CPU or case temperature points, with its corresponding percentage speed. A typical example for case fans associated with CPU temperature could be:

• 20 ºC → 20% PWM (Minimal RPMs, practically inaudible).
• 35 ºC → 30% PWM, slight improvement over the minimum.
• 50 ºC → 50% PWMThe fan already pushes quite a lot of air but is still reasonably noisy.
• 65 ºC → 100% PWMThe fan is set to maximum speed to evacuate all the heat.

That scheme is very similar to 20% – 30% – 50% – 100% Setting the temperature to 0/35/50/65°C is an excellent starting point. From there, you can adjust the temperatures or percentages to suit your case and your noise tolerance.

3. Adjust the slope and avoid oscillations

When you draw the curve in Smart Fan 5 or any other graphics editor, try to make sure the The slope should be gentle in the lower/middle area (up to about 55-60 ºC) so that small changes in temperature do not generate large changes in RPM.

At the high end, above 70°C on the CPU, the curve does make sense. be more aggressive This allows for quick response to heat spikes and prevents the CPU from reaching its limits. This combination results in a system that is quiet during light tasks but performs strongly under stress.

Whenever the BIOS allows it, it is very useful to enable or adjust the hysteresis Regarding the fan: a temperature or time buffer that prevents the fans from changing speed for minimal variations. This way, if the temperature fluctuates by 1-2°C around a point, the fans don't go haywire, constantly increasing and decreasing their speed.

4. Specific curves for CPU, case, and GPU

The CPU fan curve is usually the most reactive and aggressivebecause the cores' temperatures rise and fall very quickly. It's common practice to link the CPU cooler fan (CPU_FAN, CPU_OPT) to the CPU package temperature and allow it to go from minimum to maximum in a relatively short range of degrees.

Case fans, meanwhile, can follow a a more relaxed curve based on case or GPU temperatureFor example, front and rear fans linked to the graphics card temperature to increase when you enter a game and decrease when you are just browsing.

If you use external software capable of reading the GPU (such as FanControl or Argus Monitor, or export logs from GPU-ZYou can create mixed profiles where the fans respond to the greater than two temperatures (CPU or GPU) or a weighted combination, resulting in very fine behavior in any situation.

Software tools: FanControl, Argus Monitor, and SpeedFan

If you find the Smart Fan 5 interface in the BIOS cumbersome, you can disable the motherboard's automatic fan modes (leaving a fairly flat fan curve or a fixed speed) and let Windows software handle the delicate work. This is where utilities like [insert utility name here] come into play. FanControl, Argus Monitor or the veteran SpeedFan.

FanControl (Rem0o's project) is one of the most interesting options available today: it allows you to build curves based on multiple sensors, linear and mixed profiles, ambient temperature compensationetc., and is frequently updated. It doesn't "fight" the motherboard if you leave it in simple mode; it simply takes control of the final value sent to the fan.

Argus Monitor, a paid but very lightweight program, offers a more polished interface, alerts, thermal data logging, and predefined profiles For silent, balanced, or performance modes. It's very useful if you want something easy to use yet powerful.

SpeedFan, although no longer updated, remains a good solution for older equipment or advanced users They need to be comfortable working with older chipsets and manual sensor mapping. It allows for very detailed control of voltages and RPM, but requires more patience to configure.

Practical examples of recommended fan profiles

Balanced profile for everyday use

Designed for those who use their PC for browsing, office work, occasional gaming, and don't want to constantly hear the fans. Here, the fans spend most of their time in low or medium RPMrising only when there is a serious load.

A typical curve could keep the case fans at 20-30% below 35-40°CThe CPU fan speed should increase to 50-60% around 55°C and reserve 100% for 65-70°C. The CPU fan can be slightly more aggressive, starting earlier, but without reaching full speed until above 70°C.

Aggressive gaming profile

If you play frequently and your priority is to maintain Fresh CPU and GPU Even if there is a little more noise, you want both the CPU fan and the case fans to increase their speed quickly from average temperatures.

Here we usually work with slightly higher minimums (30-40% even at idle if you don't mind some constant noise) and faster transitions to 80-100% when the CPU exceeds 60-65°C or the GPU goes above 70°C. The idea is to have maximum airflow during a gaming session, sacrificing silence for thermal stability.

Silent or minimal noise profile

This is the right approach to office equipment, HTPCs or nighttime PCswhere noise is a major concern and the CPU and GPU aren't under heavy load. Here, the priority is keeping the fans running at their lowest possible speed most of the time.

You can allow higher temperatures, as long as they are within safe values, and associate curves where the speed does not exceed 40-50% except in extreme situationsOn some fans with 0dB mode, you can even configure 0% increments so that they stop completely below a certain temperature, provided that the motherboard and the fan itself can support it.

Typical problems when adjusting curves and how to avoid them

Never set it to 0% unless the fan can handle it.

Although it sounds tempting, you shouldn't fix a point on the curve to 0% speed Unless you're absolutely certain that your fan and motherboard support a safe stop mode. Most fans require a minimum duty cycle (20-30%) to start with reliability.

If you configure values ​​that leave the fan stopped when it shouldn't, you can generate localized overheating or dead zones of air where heat accumulates. It's always best to leave a small but real minimum, especially for CPU fans or radiators.

Incorrectly matched connectors and headers

Another common pitfall is plugging any type of fan into any header without checking anything. Make sure the 4-pin PWM fans connect to headers configured as PWM and the 3-pin ones to DC mode headers. Furthermore, it respects the logical assignment of each connector:

• CPU_FAN for the main fan of the heatsink or AIO pump as recommended by the manufacturer.
• CPU_OPT for the second CPU cooler fan or tandem fans on a radiator.
• SYS_FAN / CHA_FAN for the front, rear, and top case fans.

Connecting a CPU fan to a case header, or vice versa, can cause the BIOS to malfunction. It fails to detect RPM where it expects it and displays errors. or that an important fan is not properly regulated.

Maintenance and dust: the silent enemy

Even with a perfect curve, if dust accumulates on the case fans and filters, the result will be worse airflow and higher temperatures with the same noiseIn addition, dust can cause sensors to give readings that are less representative of reality.

It's a good idea to clean the inside of the PC, the heat sinks, and the fan blades. every few monthsEspecially if there are pets, smoke, or a lot of dust in the air. This allows the air to circulate properly and ensures your curves maintain their shape over time.

ambient temperature and seasonal changes

Adjusting a curve in winter with the room at 18°C ​​is not the same as adjusting it in summer at 30°C. room temperature directly affects resting temperatures You can see how they increase under load. If you notice that your PC runs hotter in the summer and the fans kick in faster, you might want to tweak the fan curve slightly.

Increase the percentages in the higher brackets by one or two points.Or, slightly advancing the point at which the fans switch to medium speeds can help you compensate for these variations without having to completely redo the profile.

Working calmly with the Smart Fan 5 profiles and, if needed, using utilities such as FanControl or Argus MonitorYou can have a PC with consistent airflow, case and CPU fans tailored to your hardware and noise tolerance, without annoying spikes or soaring temperatures when gaming or rendering. Once you understand the relationship between sensors, PWM, RPM, and fan placement, fine-tuning these details ceases to be a headache and becomes a fairly simple way to customize your system exactly to your liking.