120mm or 80mm fan(s) for blow hole?

[dan_hxff]

I'd like to reduce case heat by making a blow hole in the rear roof of my PC. It's an old ATX design, not new, so I don't mind carving it up. I have an intake fan in the front bottom. I may even move that one to the floor of case and suck up cool air from the tile floor. I would elevate the case on 1/2 inch blocks for this fan scheme.

My question is, which is quieter and which moves more air for this blow hole? In sum, which choice is most effective?

o Use one Panaflo L1A 120mm

o Use two Panaflo L1A 80mm

o Use two NMB 80mm http://www.svc.com/80nmb253pinf.html

Thanks
Dan

[dan_hxff]

Also instead of buying Panaflo I'm thinking of getting a bunch of these for general case cooling and for interested friends.

o Any opinion on these 80mm NMB fans: http://www.svc.com/80nmb253pinf.html

o Any opinion on these 80mm SVC fans: http://www.svc.com/powcool8031.html

o Panaflo L1A 120mm .... anyone have good cheap source for these?

o And isn't there an NMB 120mm that's supposed to be quiet? Any source for these? Seems the electronics surplus outlets are better than the computer stores.



Thanks
Dan

[dukla2000]

which is quieter

the 80mm

and which moves more air

the 120mm

Right - so you have to compromise A Panaflo 120mm L1A is 69cfm, 30dB(A) at 12V. A pair of 80mm L1As are 48cfm, 24dB(A). In reality you need to factor in your front intake (what fan/cfm is it?) as well as your ambient temps. Unless you have exceeding high ambient temps (say over 30C) and/or a very messy case my rule of thumb says 25-35cfm through your case is plenty.

And that quiet NMB 120mm - see my sig. At 5V it is about 24cfm and somewhere under 15dB(A) which is my total case 'fannage'. Yes - I got it at an electronics components supplier rather than a computer place.

[dan_hxff]

.....very messy case my rule of thumb says 25-35cfm through your case is plenty.

Many thanks for that info and NMB 120mm information

Dan

[Sleeper]

I'd still go with the 120mm.
You can undervolt it to 7v and it would move 40cfm at only 20db.
Thats only 8 cfm less than 2 80mm L1a's, but at less than half the noise (20db vs 24db)!