[SOLVED] 120mm vs 140mm RPM and fan noise?

[Netherspark]

I'm soon switching to a smaller case and will have to swap my 280mm radiator for a 240. And when idle I currently keep my 140mm fans at around 300rpm to keep the system as quiet as possible, but 120mm fans can't generally go that low and would be running 500-700 rpm when idle.

Am I correct in thinking/hoping that the 120mm fan at 500rpm shouldn't be much louder than a 140mm fan at 300rpm?

 

[scout_03]

list all parts in system board case model and fans if they are 3 or 4 pins ones with names of them .

 

[yaggaz]

I'm soon switching to a smaller case and will have to swap my 280mm radiator for a 240. And when idle I currently keep my 140mm fans at around 300rpm to keep the system as quiet as possible, but 120mm fans can't generally go that low and would be running 500-700 rpm when idle.

Am I correct in thinking/hoping that the 120mm fan at 500rpm shouldn't be much louder than a 140mm fan at 300rpm?

I recently put a dark rock slim on my i7700k that comes with a silent wings 3 low rpm fan. I have it set to silent in the bios. Took my cpu temps from 70c - 78c under load down to 40c to 50c under load.

The point is I think I remember the silent wings fan running at 600rpm and I couldn’t hear it going even when I put my head near the open case. I’m a silent nut too. It’s a 120mm fan

 

[Karadjgne]

Depends on the fans. Entirely. Pwm fans will go that low, very few DC will as they avg 60% duty cycle mostly. And thats just stats, beyond that is the fans themselves, big difference in the Arctic or Noctua and the old Corsair SP's. Generally if you keep a decent fan below @ 900rpm it'll be quiet-silent

 

[Netherspark]

Well I don't yet have any specific fans in mind, but top of the list are the upcoming EK Vardar S fans bundled with the new EK AIO. Those are stated to have a 550rpm minimum.

Also considering the Alpenfohn Wing Boost 3. And I'd happily give the Noctua 12x25 a go but they haven't got around to releasing the black versions yet.