Fans, few+fast vs plenty+slow

[Audigex]

If we assume I'm using only, say, 120mm fans, what's better. 3 of them running fast, or 6 running slow?

I'm looking at cases, and thinking of something around the antec 900 level - although I'd quite like a similar case for £20 less. But I'm trying to decide how many of the fans I'd actually need.

System will be a Q6600 with a nvidia 8800GT or better (SLI is a possibility in the future), 4gb (2x2), probably 3 HDDs (with one possibly being a raptor) and a 650W? PSU. What do I need to handle the heat?

[Mul.]

The real answer would be "it depends". Mostly on the layout of the case, the components used and the orientation and type of CPU cooler used. Both would happily take on a system like that, even 3 fans at a low speed actually.

The key is to buy any well built case with at least one front intake and one rear exhaust, where an additional exhaust/intake at the side or ceiling is just a bonus. For most high end rigs, a couple of intake and exhaust 120mm fans operating continuously at around 900-1300RPM is more than enough to keep things cool but also acceptable in terms of noise level.

[marsey99]

1300rpm is about when 120mm fans become heard, so you want fans that max at that speed or faster ones and a controller.

i have 4 120mm fans and 1 140mm fan in as my case fans and they all spin about 1200rpm and my gpu spins @ 56% which keeps it about the same sound level.

i have 3 in 2 out with 1 120 front/base/side in and the 140mm in the roof with another 120mm fan sucking out.

you can hear its on but its more of a hum than having less fans spinning faster, if i turn the 120mm fans upto 1600 rpm and the gpu fan to 100% it does sound like it should take off.

[Mul.]

^^ Agreed.

I find around 1100-1200RPM to be the sweetspot with the 120mm fans. As you say you can tell that the system is on due to the air being pushed but motor noise is basically inaudible.

[Monkey]

Cosmos s