Hot hardware is disgruntled hardware, and with temperatures reaching new highs around the world this summer, your PC fans play a critical role in how efficiently your valuable components perform. This guide explains how to tune your PC’s fans for the best possible cooling because you didn’t queue for days to get your expensive new graphics card only to get supercooled after all. (Temperature considerations also affect Valve’s Steam Deck portable gaming PC, but alas, you can’t move its internal fans.)
There are a few important concepts that you should be aware of when it comes to setting up different PC fans. Let’s tackle them one by one. Knowledge must flow quickly, like air in a well-configured system.
Airflow direction
Let’s start with the basics. How you point your fans determines whether they will suck in cold air or blow hot air out of your system. Some fans have an arrow indicating the correct direction of flow. If it doesn’t, a good rule of thumb is that air will almost always come from the front, where the brand sticker would normally be. The air exits at the back, where technical information about the fan can be written. Our guide to which way your PC fan blows can help if you need it.
The type of fan also matters, although much less than their correct setting. Higher static pressure fans are ideal for moving air through tight water-cooled radiators. High airflow fans are great for suction or exhaust in your case as they can move large volumes of air.
Positive and negative airflow
When fans pull in more air than they push out of the PC case, positive pressure is created. Negative pressure draws out more air, often creating a vacuum effect. For optimal cooling performance in a standard system, you want to be a bit more on the positive airflow side. (This setting usually results in more dust entering your computer, which can be reduced with dust filters or more frequent cleaning.)
How to achieve positive airflow? Easy: just install more supply fans than exhaust fans, or start supply fans slightly faster than exhaust fans if they are the same number. Speaking of…
intake vs exhaust
The location of the air intake and exhaust can be the most important point for proper fan placement. The idea is simple: fresh cool air in, hot air out. Generally, you want to have both intake and exhaust fans. (There may be exceptions to this, such as in small form factor builds.)
Example A: Take the popular Lian Li O11 Dynamic case. A solid fan configuration will include suction fans at the bottom and exhaust fans at the top, as shown in the image above. Fresh air will enter the case, cooling your components. The hot air generated by your equipment rises and exits through the overhead exhaust fans.
As an example B, let’s look at the more traditional Be Quiet Silent Base 802 case. The optimal fan configuration includes suction fans on the front of the case. You will also want to add overhead exhaust fans. The addition of an exhaust fan on the back of the case completes the optimal setup.
This configuration allows cold air to enter from the front, while hot air from the CPU and GPU exits from the top and rear of the case.
In a standard desktop PC, you need at least one supply and one exhaust fan. Some cheaper cases include only one intake fan on the front of the PC or one exhaust fan on the back. Spend a couple of bucks on another fan so you have both.
Push vs. drawbar for liquid coolers
Fans located in front of the liquid cooler’s heatsink, with air flow going from front to back, will “push” air into your system. If you flip the fans over and place them behind the heatsink, they now “pull” air through your liquid cooler. (as in the picture above)
What is the best setting? Most tests show little difference between pushing and pulling, but we can bow slightly to “pushing”. Generally, this will work best in most cases and give you efficient performance.
Case airflow and your processor
AIO liquid cooler: If you’re cooling your CPU with an AIO, optimal settings include placing the heatsink in the front or top of the case. Both work fine. To prioritize GPU cooling, you should place an AIO CPU on top of the case as an exhaust. This will make the CPU slightly warmer, but your GPU will stay cooler.
tower air cooler
In a traditional tower air cooler, it is best to place the fan on the heatsink of the cooler to force air towards the rear of the case. In the example above, the open GPU shroud also blows hot air upwards – a typical setup for a gaming rig. This will raise your CPU temperature slightly when using an air cooler; You can reduce the heat level with the optimal fan airflow.
How about your GPU?
Standard GPUs with open shrouds blow a lot of hot air into the case – even more than your CPU if it’s a powerful graphics card. What can you do to maximize cooling and airflow?
If your case allows, install fans that blow air up to the GPU from below. This will blow cold air directly to the intake fans on the GPU itself. If this configuration is not possible for you, install a front supply fan in combination with the appropriate top or rear exhaust fans as described previously. Again: you always need at least one intake and one exhaust fan in your system, and that’s doubled if it’s a gaming rig.
Fan curves and chassis selection
There are two last important points to consider. First, case selection can help a lot in optimal fan airflow. Our guide to buying the perfect PC case can help, although you should be able to if you follow these general guidelines:
- Use a case with a mesh front. They will have much better airflow than cases with closed or glass fronts. Examples include the Fractal Design Meshify series and the Be Quiet Silent Base 802 mentioned earlier.
- If you’re running hot, powerful hardware, make sure the case is large enough to accommodate the necessary fans. If you want to use a smaller case, consider using liquid cooling for more efficiency.
Second, use fan controllers to determine the best noise-to-performance ratio you can find. Most mid-range and high-end motherboards include fan software either in their BIOS or as a Windows application. Asus Ai Suite 3 is an example of this. You can set the CPU and case temperatures based on actual temperatures, which can ensure quiet operation. Similarly, fans can turn up the power when needed to make sure everything stays cool.
If you need more advanced fan curve control, there are also hardware controllers from Aquacomputer, Corsair and EKWB that allow you to fine-tune your fan curves even further. You can also set the fan speed on the GPU or use temperature sensors with these more advanced devices, but these are overkill for most people.
That’s it: now you know everything you need to know about optimal fan placement for the best possible cooling. Our guides to checking your CPU temperature and your graphics card GPU temperature will help you make sure everything is running smoothly. May you have a low temperature!