A different way to judge fan performance....

Bluefront · Post by **Bluefront** » Thu Nov 09, 2006 4:22 am

Let's get practical.....computers are getting smaller all the time. There is just not the space for a large number of fans. So what I'm suggesting is a different way to judge a fan. I'm looking for a 120mm fan that will run quietly at 5v....and at the same time have the capacity to blow a lot of air(not so quietly) at 12v, when the computer is being stressed.

Most of the favorite fans of SPCR will not do this. The Nexus and Yate Loons are an example. 1200rpms will not cool my computer, which runs relatively hot components that need more than 40cfm to stay cool under stressing.

We need a new favorite 120mm fan, quiet at 5v, powerful at 12V. What will it be?

tweakt · Post by **tweakt** » Thu Nov 09, 2006 8:36 am

I'm looking for the same. My P180 is loaded with disks and an OC'ed Opteron. The ambient temperature in my room can fluctuate quite a bit as the sun rises, as much as ten degrees F. The fan in the lower chamber just died so I'm looking to replace it, and I'd like to control the new fan's speed in response to HD temps.

BillyBuerger · Post by **BillyBuerger** » Thu Nov 09, 2006 2:55 pm

You know, I think Seasonic needs to start selling their fan controller as a separate product. Pair it with a medium speed ADDA fan like from their PSUs and you have a fan that will be very quiet at 3.8V when things are cool. Yet can provide plenty of cooling and noise at 12V when needed.

jaganath · Post by **jaganath** » Thu Nov 09, 2006 3:17 pm

The Scythe S-Flex SFF21F is the fan for you, 60CFM+ @ 12V/1600rpm, almost silent at 5V. There are two ways of approaching the heat/CFM problem: one is to dial up the CFM's to cope with the heat, the other is to dial down the heat to match the CFM's/. IMHO the latter approach is more conducive to truly inaudible operation.

Bluefront · Post by **Bluefront** » Thu Nov 09, 2006 4:23 pm

Not so easy for many people, me included. I want the performance of a P4-3.4, but my board cannot lower the voltage to the chip. And since I like everything else about this particular board, and the NW 3.4, my only option is a fan that can cope with the heat.

IMHO.....since computers are at idle temps most of the time, the computer can be made quiet most of the time, and only slightly noiser under stress.

That Scythe sounds ok, maybe a tad weak for a hot setup.

Felger Carbon · Post by **Felger Carbon** » Thu Nov 09, 2006 6:52 pm

To get more CFM, you can do one of three things:

Increase the RPM of the one exhaust fan.
Use more than one exhaust fan.
Use a bigger exhaust fan.

At the moment, you're concentrating on the first alternative, using one 120mm fan. The Antec NSK2400 and P180 both have two 120mm exhaust fans, which will provide the same CFM as one at 15dBA less sound level. And one of my computers has a single 220mm fan. Consider the other alternatives.

Why, some people run garden hoses in and out of their computers to export the heat, so there's more than three ways to skin a cat!

Bluefront · Post by **Bluefront** » Fri Nov 10, 2006 2:41 am

Keep the word practical in mind. It's practical to have the exhaust, or the intake for that matter, at the rear of the case, since it's out of the way, and quieter back there.

Tower cases are more practical than other types, since they can sit on the floor, out of the way, off the desktop.

Most tower cases have room enough for only one fan at the rear, other than the PSU opening.

Unless you want to mod cases extensively, you are stuck with available designs. Building your own case is not an option for most.

Water-cooling is not an option from a practical sense.

Which brings us back to a case with one fan opening in the rear, usually a 120mm max size. If you want to be practical, you deal with what you have available. That's why I think we need a new favorite powerful fan, capable of running quietly when not under stress. This does not seem to be out of the question. Powerful fans can have sleeve bearings, and quiet motors. And they only need to be noisy, when blowing a lot of air.

Tzupy · Post by **Tzupy** » Fri Nov 10, 2006 3:37 am

Your problem is not the fan IMHO, but the P4. My Nexus case fan and the fan in the S12E+650 handle very well a C2D E6600 and a 7900 GTX.
The exhaust air is barely warm when playing Oblivion, and right now it's cool. The Nexus fan on the SI-128 is not yet spinning.

Bluefront · Post by **Bluefront** » Fri Nov 10, 2006 3:57 am

You're missing the point.....there are other things in cases that create a lot of heat besides the CPU, and need more CFM than a Nexus can provide. Most people are not satisfied any longer with cool-running components.

Multiple hot hard drives, two hot video cards....etc. This is not a computer a single Nexus fan can handle......so what's a quiet alternative that can handle the heat?

Tzupy · Post by **Tzupy** » Fri Nov 10, 2006 4:22 am

Well, I thought about a fan design that would be better than the Nexus. It would have to start below 5V, have the same kind of frame (more 'open' than other fans, resulting in less turbulence noise from the fan blade tips) and maybe blades like the ones of the Sharkoon (with golf ball potholes to minimize turbulence). And to minimize the noise at the source, some noise dampening stuff integrated into the fan.
But a better approach would be a case with strong positive pressure, coming from 3 fans on the bottom, 120x38 mm for better handling of back pressure, and a sound dampening / dust filtering contraption on the whole bottom of the case. Case feet would have to be tall, probably same height as the ones in the Nexus Breeze, but allowing more airflow.
No exhaust fans, which would be directly audible, but all possible exhaust areas should be covered by large heatsinks (separated for CPUs, GPUs, HDDs), heat being transferred by flexible heatpipes.
Oh yes, and a passive PSU that is cooled by heatpipes. An area of 8 x 15 cm could accomodate a PSU heatsink that would nicely dissipate upto 50W.
I sure got carried away...

jaganath · Post by **jaganath** » Fri Nov 10, 2006 5:20 am

Most people are not satisfied any longer with cool-running components.

That may have been true in the pre-Conroe era, but now that C2D is here, you really can have your performance cake and keep it silent too. Sure, graphics cards are still too hot but the overblown claims of ~300W for the nVidia G80 etc are now shown to be almost 50% too high. That said, I can appreciate your predicament, you already have a hot processor and don't want to spend a fortune buying a new CPU, M/B and RAM. In that case high-CFM fan is a necessity, but for anyone building a rig from scratch today, the advice is: don't start from here.

maybe blades like the ones of the Sharkoon (with golf ball potholes to minimize turbulence).

Two things:

a ) the dimples on a golf ball are actually designed to cause turbulence, this reduces overall drag on the ball

b ) I think they're just a gimmick on PC fans.

Epsilon · Post by **Epsilon** » Fri Nov 10, 2006 7:03 am

Bluefront,

If I were you, I would try to fit a couple of 140mm Yate Loons (medium speed version) which start at 5v and can go up to 1500rpm, they have a good sound quality, made mainly of airflow. They are very quiet at 5v. They have a massive airflow too.
Space for fitting them, of course, may be a problem...

GHz · Post by **GHz** » Fri Nov 10, 2006 12:30 pm

Just to mirror the above comment: get a medium speed Yate Loon fan. You can get the D12SM-12 which has a higher top end of around 1600 RPM vs 1350 of the L version. The Scythe fans are also very good (although acoustically a little behind the YL) but in my experience they have problems with PWM.

Bluefront · Post by **Bluefront** » Fri Nov 10, 2006 3:53 pm

Well there are very few cases readily available, that can use a 140mm fan on the rear. Nothing I own would handle one. That's why I think a 120mm fan that is fast enough, is the one to go after.

I do have a medium speed yate loon (sleeve bearing, blue leds) in one case. I will do 1600rpms, but could not handle PWM control without an M-Cubed attenuator. It's ok, but doesn't handle airflow resistance very well.

I'm using several Globe fans, sleeve bearing, will do 1800rpms. They aren't bothered by PWM, and handle resistance better than the Yate Loon. They are just not available any longer.

The only Scythe fan I've ever heard is the model that comes with a Ninja. It's very quiet, but is too weak to be much use in a hot setup.

Keep on looking I guess....