Log Minimum Distance from Fan to Vent Grill?

[Sean Crees]

I could have sworn i read someone else test this, but i can't for the life of me remember what it is or be able to find it through searches.

What's the optimum minimum distance a fan (like a gpu fan) should be from a vent hole to minimize excessive noise? I'm designing a case for myself and have about 11mm of excess space to work with and am thinking i should give the GPU fan's some extra space to reduce excess noise. I'm currently leaning towards 1/4 inch.

 

[robbee]

@K888D wrote about fan performance close to a flat surface but that's not really about noise though: https://lazer3d.com/2017/02/05/fan-performance-testing-part-1/

For me personally, I've always taken about 10-15mm distance between restrictive vent holes and intake fans as a rule of thumb. You can also experiment with vent hole patterns to minimise noise.

It's not entirely academic, but it's easy to test yourself by the way. Take a piece of cardboard and cut out your vent pattern. See how close you can hold that to your fan/gpu until it starts to get too noisy. You can use a file punch to make holes quickly.