You can have all the powerful hardware to build your PC, but without the quality fans along with the correct number of fans to be used, your graphics card may crash or memory sticks may fail badly. Fans are very important to cool various components protecting the inside of the computer. But many have a common question about whether to mount bigger-sized fans or smaller ones, additionally, how many fans does someone’s system need? The conundrum of using 2 x 140mm fans or 3 x 120mm fans throws this kind of debate. You need to know your system, your kind of activities of yours, relative pros and cons of different-sized fans before choosing one combination.

Difference Between 2 x 140mm Fans and 3 x 120mm Fans
There can be several considerations to make before deciding which one is better- 2 140mm fans or 3 120mm fans. The amount of airflow, noise, kind of users, quality and price of fans, etc. must be well thought out.
Before going into any further details about 2 x 140mm fans and 3 x 120mm fans, let’s have quick look at the core differences between 140mm fans and 120mm fans below –
140 mm Fans | 120 mm Fans | |
Dimension | 140mm x 140mm x 25mm | 120mm x 120mm x 25mm |
Weight | 0.234 LBS | 0.171 LBS |
Compatibility | Limited compatibility | Compatible with most cases |
Cooling and Airflow | Higher airflow | Decent airflow |
Static Pressure | 1.4 mm-H20 | 1.55 mm-H20 |
RPM (Revolutions per minute) | 550 – 1250 ±10% RPM | 525 – 1500 ±10% RPM |
Air Flow Amount | 50.2 CFM | 41.8 CFM |
Volt | 6V-13.2V | 6V-13.2V |
Noise | 22 dBA | 26 dBA |
Price | Slightly more expensive | Cheaper |
As you can see in the above table that the 140mm fan has a lower speed than the 120mm fans but the 140mm has higher airflow than the 120 mm fan. However, the airflow amount of the 140 mm fan is only 8.4 CFM higher than 120.
For 2×140 fans the airflow will be 2 x 50.2 = 100.4 CFM.
Whereas the airflow amount for 3×120 fans will be 3 x 41.8 = 125.4 CFM.
So practically, 3×120 fans are able to push more air than 2×140 fans.

1. Noise
Most of the users would like to have a minimum of noise coming from their computer fans. It largely depends on the size of the fan. The smaller the fan size, the more rotations from its wings. Hence, the 120mm fan would exert far too much noise compared to the 140mm fan. You can imagine the kind of noise the combo of 3 x 120mm fans will produce. In this case, I would say that the 2 x 140mm fans beat the 3 x 120mm combo.
2. Airflow
3 120mm fans are likely to push more air through the system’s ventilator when you compare the same with 2 140mm fans. If you play too many 4K resolution games or do lots of video editing, then there is a good chance that a good amount of heat is coming out of the processors (CPU and GPU). So, to cool down the internal components, fans should be able to direct much air in and out of the system. Hence, we can say that advanced users should go for 3 x 120mm fans for proper air circulation whereas normal users will not require more than 1 or 2 140mm fans.
3. Quality
Quality is probably the most important aspect of choosing the right fan. An arrangement of good quality fans be it 120mm or 140mm, will always win against average-quality fans.
4. Price
The price of a 140mm fan is naturally more than the price of a 120mm fan because of the size difference. But when it comes to adding multiple fans, in our case, 3 x 120mm fans will definitely cost you more than 2 x 140mm fans. However, the price also depends on the quality of the fan regardless of the size.
If you are looking for a 140mm fan or 120mm fan, then here are some worth looking into.
Frequently Asked Questions
Is It Better to Have 2 140mm Fans or 3 120mm Fans?
3 x 120mm fans can push more air than 2 x 140mm fans. But 3 x 120 mm fans will be so noisy than 2 140 mm fans. So, obviously 3 x 120 mm fans are better than 2 x 140mm fans, but if your PC doesn’t require heavy airflow, then it is recommended to use 2 x 140 fans to get a calm environment around your PC.
Are 140mm Fans Better than 120mm Fans?
Yes, 140mm fans are always better in terms of airflow and cooling as compered to 12omm fans. They also produce less noise than 120mm fans and required almost save amount of power to run. The only drawback of 140mm fan is that it has limited compatibility.
What Is the Best RPM for 140mm Fans?
There is nothing called the best RPM for 140mm fans. However, the maximum RPM of a 140mm fan can be 1300 RPM and minimum RPM can be 550 RPM.
What Is the Best Size Fan for A PC?
The most popular size that is used in modern PC cases is 120mm. However, there are other sized fans available on the market too. For example, 80mm, 92mm, 140mm, 200mm, and various other configurations.
Conclusion
After considering everything, I can tell you that the 2 x 140mm fans are better in several aspects than the 3 x 120mm fans. The statement can change depending on the activities you carry out. Remember this, the good quality 3 x 120mm fans are worth having compared to average quality 2 x 140mm fans. But there is no competition for good quality 2 x 140mm fans no matter how many fans you add with the 120mm arrangement.
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