Case manufacturers rarely explain why some fan mounts take one size and others take a bigger one, so builders are left guessing which fits their chassis. The 120mm vs 140mm fan question comes up constantly for that reason, and the Einarex EX12A settles half of it simply by being the size that fits almost every mid-tower on the market.

Quick Answer

The Einarex EX12A is a 120mm fan priced at R249, reaching up to 82.9 CFM and 40.7 dBA at full PWM speed. A 140mm fan moves a similar volume of air at a slower, generally quieter spin, but only if your case actually has 140mm mounting holes to begin with.

📐 Why size is mostly decided by your case

Before airflow or noise ever enter the conversation, the fan size question is really a mounting question. Most compact and mid-tower cases include 120mm points at the front, top, and rear, which is why the EX12A fits such a wide range of builds without modification. Larger 140mm mounts exist mainly on bigger cases with wider front panels, and a case built only for 120mm fans simply cannot accept a 140mm unit no matter how good the specs look on paper.

Where 120mm has the edge

Because a 120mm blade covers less surface area, it typically needs to spin faster to move a given volume of air. The EX12A's 82.9 CFM figure at full PWM speed reflects that faster spin, which is one reason smaller fans are often paired with higher RPM ratings than their 140mm counterparts.

🔊 Noise and airflow at each size

A 140mm fan can often reach similar airflow to a 120mm model while spinning more slowly, since its larger blades sweep more air per rotation. That slower rotation frequently makes 140mm fans a touch quieter at equivalent airflow, though a well-tuned 120mm fan with proper PWM control, like the EX12A staying under 40.7 dBA at its peak, can close much of that gap in everyday use.

🛠️ Fitting the right size to your build

Check your case manual or the mounting holes themselves before choosing either size, since guessing wrong means a fan that simply will not bolt in. Case fans sold in 120mm form cover the widest range of chassis, which is part of why they remain the default recommendation for most gaming PC builds. Anyone shopping for a complete chassis rather than just a fan can browse Einarex's case lineup to see which mounting sizes each model supports before committing to fans. Full specs and current stock for this exact model sit on the product page for the EX12A, worth a look once you have confirmed your case takes a 120mm fan.

Frequently Asked Questions

Can I fit a 120mm fan where a 140mm one used to be?

Only if the mounting holes on your case support both sizes, which many mid-tower cases do at the front panel; check the manual first.

Does a bigger fan always mean quieter running?

Not automatically, but 140mm fans often reach a given airflow figure at a lower RPM than a 120mm fan would need, which can help.

Why does the Einarex EX12A only come in 120mm?

It targets the mounting size used by the widest range of gaming cases, keeping compatibility simple for most builds.

Is 82.9 CFM strong for a 120mm fan?

Yes, that figure sits at the higher end for a fan this size, especially paired with PWM control for adjusting speed.

Do 140mm fans cost more than 120mm ones?

Pricing varies by brand and model rather than size alone, so compare specific units rather than assuming size dictates cost.

Ready to confirm which fan size actually suits your case? Choose the 120mm Einarex EX12A PWM fan at R249 through Evetech's case fan range, if your case takes the more common 120mm mount.