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Question about bigger case fans > 120mm.

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killem2

Member
Joined
Jan 6, 2005
So i am looking to build a case. It is gonna be made of wood. Gonna be hot. I got the placement down, but since it is completely custom I have quite a bit of leg room to do what I want.

I want the case to stay cool of course, noise at first wasn't an issue but I wasn't aware just how loud some 120mm can really get if you want constant air flow.

What about larger fans like 250mm, 220mm, 200mm ect.



I guess I am trying to get the strongest air flow for the most reasonable noise level (I don't want a vaccum or hair dryer sound all the time)



Since it is a custom case I have the freedom for any size I choose.

What do you suggest?
 

muddocktor

Retired
Joined
Nov 1, 2001
Location
New Iberia, LA
I just recently got my first experience with case fans larger than 120 mm with the HAF922 case and I can say that the 200 mm fans that came with the case are pretty darn quiet and move a decent amount of air, but with low static pressure. They are the 700 rpm variety on this page. I also bought this 1000 rpm model to add to the case side and I find it to be a bit noisier than I thought it would be, but it does move more air too. If I had to buy it over again I would get the 700 rpm model for the case side door.
 
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killem2

killem2

Member
Joined
Jan 6, 2005
Nice. I figured up that my case is going to be a 13" wide x 13" tall x 18" deep. So on the front I have a few options: (basically 332mm (w) x 240mm (t) of space).

Front Options

6x 80mm fan (stacked)
2x 120 mm fans
2x 150mm fans
1x 160mm fan --- 1x 200mm fan.


I am intrigued at the concepts of a 200mm fan :) So if I did one 200 mm fan on the front, here is what I have as far as options on the top and back. (i was trying to avoid this time around of using the sides for fans at all)

===============================================

Top

I can fit it looks like:
4x 80mm fans They would basically be toward the front on the left and right of the dvd drives

or

1x 80mm to 150mm fan (if I choose to not full up the narrow channel like areas)

or

1x 80mm to 150mm fan + 4x 80mm fans.

The top has a few spaces along the sides of the dvd drives on each side. Then just large open space, basically over my gpu/pci slots.

===============================================


The Back

The back has two odd ball open spaces to use. One below the psu right behind my cpu cooler which I would love to have a good fan here.

The space under the psu AND the space above the PCI bays each allow for

4x 80mm fans
1x 120mm --> 160mm fan



Is it bad to have mis matched sized fans for intakes/exhaust? I am pretty sure the 80 mm fan monster setup is going to be far to loud to be practical regardless of how much air but i mentioned just in case there is a wonder fan out there :) Besides less wires inside = bonus!

The top is also tricky for me to decide on. I don't see the frontal ones pulling out much hot hair because it hasn't even blew over the motherboard at that point yet, but it will by pass the rack of 6 HD bays. I mentioned for your info but I think it'll end up being pointless. The space towards the back of the pc on the top which is above the gfx card/pci slots could house a nice exhaust fan, as well as the back.




I just read here: http://www.technibble.com/case-cooling-the-physics-of-good-airflow/

That to get a good airflow and what they call a "positive pressure channel" I take the cfm from the intake, and subtract the cfm from the exhaust.

I figured up, I could go 200mm in the front (just one)

Then 3x 140mm fans

It would leave the case at -80.2 cfm from the intake.

Am I reading that right?
 
Last edited:

Conumdrum

Member
Joined
Sep 15, 2007
Location
Small town Emlenton, PA
You DON'T want 80mm fans. There is a simple reason we got away from them. They spin at a higher RPM and make more noise. If your building a custom case stick with 140mm for case fans or 120mm fans. Putting a 200mm on the side and or top is pretty nice. They really do work good and quiet for pulling air out on top or pushing a bit more on the side.
 
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killem2

killem2

Member
Joined
Jan 6, 2005
I figured to pass them up. So will it be ok to do 1x 200 mm fan in the front or do you think 2x 140 or 2x 120 for intake is better?
 

Conumdrum

Member
Joined
Sep 15, 2007
Location
Small town Emlenton, PA
a 200mm fan can push some air, but I dunno. You need some pressure to create some good airflow. A 200mm is pretty poor for pressure ratings. Methinks two 140mm is the sweet spot.

If your putting HD's in the lower front, then yea, I'd go 140. The 200mm has a very large dead spot in the middle. It's all about balance I guess.
 
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killem2

killem2

Member
Joined
Jan 6, 2005
I see. Well i can certainly do that. So that article about the greater cfm outtake vs cfm intake isn't accurate?
 

Conumdrum

Member
Joined
Sep 15, 2007
Location
Small town Emlenton, PA
It depends what you want. The CFM in/out isn't the biggest deal to worry about. Having good airflow is enough in most situations. You can do it how you like though. I would use positive pressure somewhat, it will keep the dust creeps in spots where the case isn't sealed.

But it's not a big deal. Two 140mm in and the same for exhaust would be just fine. They will be a bit quieter blowing the same CFM as a 120mm would be, less RPM.

You just want enough airflow to keep the inside air from getting to warm, impacting your temps.
 

muddocktor

Retired
Joined
Nov 1, 2001
Location
New Iberia, LA
For case ventilation, a front 200o mm fan will do well. That is what the HAF922 comes with and no problems with it inputting adequate air for good cooling, even without the side fan. And it uses both a 120 mm fan on the back side and a 200 mm fan on the top rear as exhaust fans. In my case, I replaced the top exhaust fan with the 1,000 rpm fan I bought extra and installed the 700 rpm fan that came installed in the top on the side door of the case (which was already set up to mount 1-200 mm or 2-120 mm fans). And I also replaced the 120 x 25 mm Coolermaster fan on the back side with a 120 x 38 mm Panaflo L1BX fan, since it's blowing into a TC PA160 rad that's mounted externally on the back of the case.
 
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killem2

killem2

Member
Joined
Jan 6, 2005
Should I go coolermaster for the 140mm fans for the exhaust?