Which is better: 3 or 4 case fans in a cold system?

Question

Cooling systems

I saw a discussion on a tech forum where a user was asking about the placement of his four case fans (all 120mm). Below is his photo:

spoiler

I have exactly the same case, but only 3 120mm fans. I will take the same mat. board (Micro-ATX), and i5 10400 or 10600 processor

. I'm interested in the following: if I put only 3 fans in the case (2 for intake and 1 for exhaust), will I have problems with airflow? Will dust blow out / stagnate air be worse? Is it worth it to buy a fourth fan in the case to place it on top (as in the photo)?

Answer 1

4 is better, but 3 is enough for your system.