Fan configuration on RAD

Hi,
I was wondering using the pa120.3 would you get better, same, or worse cooling with 6 quiet 40cfm fans in push and pull configuration compared to 3 somewhat quiet 80cfm fans pulling air through the RAD?

Another question I had was what about the 6 fans without a shroud compared to 3 fans with a shroud does the shroud make that much of a difference?

well, they use 120 fans. so they aren't covering the whole surface area that is meant to be cooled. I would vote for worse if anything. Besides I always found smaller sized fans seem to be louder than a larger fan pushing the same CFM

actually all of the fans would be 120mm I was stating the cfm (air flow) in the original post not the size.

dvanlinge said:

actually all of the fans would be 120mm I was stating the cfm (air flow) in the original post not the size.

Click to expand...

Wow. ok sorry. its early On that note, I'll be back in about an hour to edit that when I'm more awake

CFM is not as usefull a number as you might think when applying them to a radiator. Fan pressure is the more important figure, because you're mounting them against an air restriction.
Yes, it's a hard figure to find with some models of fans, and most retailers don't post this info.

Personally I'd go with the 6 40 cfm fans though, mainly because about any triple radiator will handle a cpu with ease. The quietness of a rig outweighs it's temperature in my book.
A computer may have great temps, but how easy is it to live with ?

Hey D,

I don't have any hard numbers to show you, though I know I saw an extension thread on the PA-series of rads and multiple fan configurations done over at XS. But I'll tell you that I went from three Panaflo Ultras running at 7V (not sure what CFM they push at that voltage, but they do 114 CFM @ 12V) to six Coolermaster LED fans @ 42 CFM, and it's been heaven on the noise level and the temps didn't change that much (actually, mine got a lot better because my waterblock didn't have a good mount. )

I don't think 6 fans provides much benefit over 3 fans ... I recall reading it was something like 3% or less depending on whose tests you looked at. But I thought the fans on the inside looked cool and helped light the case a bit since they were LED fans, so I figured why not.

As far as shrouds, I have no idea. I know they help a good bit. I'd like to run with a shroud, but I don't think I have enough room for one on both sides of my rad with all the fans, and I don't know if putting one just on the front would affect the airflow enough that it would make the fans on the back make that pulsing hum they do when one set is pushing more air than the other (like when my front fan filters get a little too dusty).

Found that thread I was talking about at XS: http://www.xtremesystems.org/forums/showthread.php?t=77260

Marci compares the PA120.3 with the HE120.3 with the PA160. Very good read. Doesn't compare too much between the same setup with one fan versus push-pull aside from the PA160, but it's still a good one to go through. At the bottom you can see where he tested a PA120.2 with a shroud and two fans running at 600RPM, 900RPM, and 1200RPM, and with the fans running twice as fast, his temps only dropped 1.7 degrees.

This is why I am asking.... currently I am running 3 of these fans

http://www.dangerden.com/store/product.php?productid=124&cat=78&page=1

Evercool Chrome 120mm Fan

80 CFM at 2000 RPM
30Db
0.38A at 12V
3 Pin and 4 Pin power connector

with a shroud and was wondering if I remove the shroud and put 6 of these fans:

http://www.jab-tech.com/YATE-LOON-120mm-Case-Fan-D12SL-12-pr-3009.html

YATE LOON 120mm Case Fan - D12SL-12
BACK AND NOW IN BLACK

Specifications:

Model: D12SL-12
Dimensions:120x120x25mm
Rated Voltage: 12 Volts
Operation Voltage: 6.5~13.8 Volts
Input current: 0.30 Amp Max
Operation temperature: -10 to +65 C
Storage temperature: -40 to +70 C
RPM: 1350 +/- 10%
CFM: 47
dB: 28



would I get the same cooling just quieter

I'd think you'd get worse temps. You'd be removing the shroud, which helps a lot, and dropping the CFMs considerably. Additionally, you'd only be losing 2 dB of fan noise for three fans (if the Evercool's are really 30dB @ 80CFM), but you'd be adding twice as many fans, so the fan noise would actually be louder overall (though airflow noise caused by resistance of air being pushed through the rad would probably be a little lower due to less CFMs).

Or replacing the 3 fans and shroud with 6 of these fans?

http://www.frozencpu.com/products/5..._iXtrema_Pro_Fan_IXP-76-14.html?tl=g36c15s562

SKU: IXP-76-14
Noise Level: 14 dB
Size: 120 x 120 x 38 mm
Fan Speed: 1400 RPM
Air Flow: 60 CFM
Operating Voltage: 8-14v
Current Draw: 0.2A
Power Consumption: 2.4w
Bearings Type: Hybrid Sleeve

Although this would be very pricy...

Oh. So it's a matter of getting rid of shrouds, then I'd stick with the 3.
Performance drops considerably when removing shrouds, even when adding fans.

And dB's are a funny monkey.
Doubling the fans adds roughly 3 dB, as it's an exponential scale, not a linear one.
So with 28 dB fans you'd get:
1 fan =28 dB
2 fans=31 dB
4 fans=34 dB
6 fans=35 dB (guestimated).

So six lower noise fans could actually be just as loud as a lesser number of louder fans, especially when they're so close in dB ratings.
Adding in worse performance due to lack of shrouds, I'd have to stick with 3.
I stand reversed!

It's not that I want to remove the shroud, it's just that if I go to 6 fans I don't have the room for the shrouds as the RAD is in the top of my case. The reason for the questions is to quiet the computer but keep the cooling performance.

Well, simply allowing better airflow (in or out) can lower the noise by lowering the resistance against the fans, and can also drop the temps.
Do your fans get any quiter or run at a lower pitch sound when a CD rom bezel is removed?

The reason I ask, three 120mm fans is alot more airflow than most cases naturally can do. So it's easy to accidently restrict them by having a box that's too air-tight.

I do notice they get a little quieter when I remove the side, I am using the Lian-Li pcg70 case and in the #2,3, and 4 5.25" bays from the top I have a 120mm fan and another 120mm fan at the bottom of the case. I have thought about just leaving the side off but then I can hear the noises from the drives.

dvanlinge said:

Or replacing the 3 fans and shroud with 6 of these fans?

http://www.frozencpu.com/products/5..._iXtrema_Pro_Fan_IXP-76-14.html?tl=g36c15s562

SKU: IXP-76-14
Noise Level: 14 dB
Size: 120 x 120 x 38 mm
Fan Speed: 1400 RPM
Air Flow: 60 CFM
Operating Voltage: 8-14v
Current Draw: 0.2A
Power Consumption: 2.4w
Bearings Type: Hybrid Sleeve

Although this would be very pricy...

Click to expand...

SilenX has a very bad reputation around here for their misleading dB ratings. Just search SilenX on the forums and see what comes up. I wouldn't buy anything by them.

Worse than that, Silenx employees have been caught posing as happy end users on the silentpcreview forums (maybe elsewhere too). At the other end of the spectrum, Yate Loon has some of the quietest fans available but tests their fans in a way that gives higher sound numbers than nearly all of their competitors. Why don't they change the tests so that they can claim 14db instead of 28? Probably because they don't need to.

To move 60CFM at 14db, you'd have to put your noise meter in the next room.

For every 3dB, the power ratio is doubled. This means a 33dB fan is twice as loud as a 30dB fan. A little food for thought.

Diggrr said:

Well, simply allowing better airflow (in or out) can lower the noise by lowering the resistance against the fans, and can also drop the temps.
Do your fans get any quiter or run at a lower pitch sound when a CD rom bezel is removed?

The reason I ask, three 120mm fans is alot more airflow than most cases naturally can do. So it's easy to accidently restrict them by having a box that's too air-tight.

Click to expand...

I think Diggrr is on the right track. If you're not controlling the fan speed dynamically, though, the question is do you get much better cooling with the side off the case or an open bay acting as an intake?

Another thing to look at is your coolant temp. Maybe you don't really need as much cooling power as you've got with the loud fans. If your coolant temp is 2C over ambient at load now, you can probably afford to use three quiet fans and let it rise to 4 or 5C.

Diggrr said:

So with 28 dB fans you'd get:
1 fan =28 dB
2 fans=31 dB
4 fans=34 dB
6 fans=35 dB (guestimated).

Click to expand...

Adding one more identical noise sources to a set of two, or two more to a set of four, adds 1.8db. Hence 28db fans would produces 35.8db.

From what I've read about the PA series, there's not much to be gained with push-pull setups. I suggest you check your coolant temps, and if they're not very far from ambient, try three Yate Loon D12SL-12's. Thermochill recommends push, but from what I've seen on the forums, most people are getting slightly better temps pulling.

dvanlinge said:

I have thought about just leaving the side off but then I can hear the noises from the drives.

Click to expand...

If you do move to quieter fans, you're probably going to start hearing those drives anyway. Here's a good place to start figuring out how to deal with that.
http://www.silentpcreview.com/forums/viewtopic.php?t=8240

noxqzs said:

For every 3dB, the power ratio is doubled. This means a 33dB fan is twice as loud as a 30dB fan. A little food for thought.

Click to expand...

Actually, percieved loudness doubles only about every 10dB. Hence, 8 fans are roughly twice as loud as one.

Hi Otter,
thanks for the info although I don't have anyway to measure the water temps, I do have 3 of these Nexus fans:

Nexus Real Silent 120 mm Case Fan Specifications
Model D12SL-12
Power Connector 4-pin & 3-pin
Dimensions 120x120x25mm
Rated Voltage 12 Volts
Operation Voltage 6.5 ~ 13.8 Volts
Input Current 0.30 Amp Max
Input Power 1.8 Watts Max
Rotation Speed 1000 RPM
Acoustic Noise 22.8 dB(A)
Airflow 36.87 CFM
Operation Temperature -10 to +65 C
Storage Temperature -40 to +70 C
Manufacturer's Warranty 3 Years

Which I think are actually Yate Loons so maybe I will just swap them out and see what happens to my CPU and GPU temps...