Where should I add new fans?

[pcwin]

Q1) Is adding a 120mm fan to A or B better?
Q2) Is adding two 120mm fans to A and C better? or A and B better?

The blue fonts are 120mm fans I intend to add for air intake into casing. I intend to add either 1 or 2 fans.

The red fonts are fans that are already in my casing CM 690 II Advanced

Other suggestions?

 

[linnemeyerhere]

Add A & B and forget about C as it will likely just screw with the flow from the 140 mm and the new B fan

 

[AddRAM]

Definetly B, and A only if it is filtered.

I don`t even see holes for A, but I assume they are there.

As Alan says, C would be useless.

 

[pcwin]

Orange arrows will be where the fans are, and air direction arrows for my casing. Thanks all

 

[pcwin]

Definetly B, and A only if it is filtered.

I don`t even see holes for A, but I assume they are there.

As Alan says, C would be useless.

There are holes and filter. See the third pic here Cooler Master CM 690 II Advanced review - Product gallery - Exterior

 

[pcwin]

I have one 140mm PWM fan, should I put at the front, top (nearer back) or top (nearer front)?

I have never use a PWM fan before, I bought it because the normal (non pwm) fan is sold out.

 

[ThrashZone]

A= might need to be a 120mm fan depending on the psu and wiring and how much room that takes up
Fit as many 140mm as you can

The only other 120mm is on the back

C= yea I don't get that one at all
My hhd rack had a floor on it so there wouldn't of been anywhere for the air to go
If you take the hdd rack out then it might make sense to put a fan there.

Case fans I would use af140 or 120's very quite fan

Think about cpu liquid cooling they work best as a intake pulling cool air in
The most logical place for it is in the floor some versions already have a 120 fan on it like the Corsair h80
Hydro Seriesâ„¢ H80i High Performance Liquid CPU Cooler

But you can put as an exhaust on the back top it's well worth getting
Or a h110 gt on the top
Amazon.com: Corsair Hydro Series H110 280 mm High Performance Liquid CPU Cooler: Computers & Accessories

Hydro Seriesâ„¢ H110i GT 280mm Extreme Performance Liquid CPU Cooler