Silent fan advice

Shingyboy · 7 May 2016 at 21:18

So I am planning to buy a new case pretty soon, either the Phanteks Evolv or the Fractal Design R5.

I am wondering if it is worth buying fans to replace those ones with the specific mindset of keeping them as silent as possible but not having really bad airflow.

At the moment I have a Thermalright silver arrow CPU heatsink and the fans on those are actually pretty quiet.

BluD · 7 May 2016 at 22:54

If you use a fan software you can get the fans that come with the evolve running very quietly, they start up around 300rpm, i had them with my phanteks primo case for a while.

If ya wanna keep a little airflow then just set them to sit at around 400 rpm at idle and set a curve so they ramp up with heat. Theyre useless if ya like turning your fans off altogether though, they make a slight clicking noise.

I dont know what the fractal fans are like but the phanteks ones are good if ya keep them going.

Shingyboy · 8 May 2016 at 01:38

What sort of fan software do you use? Do I have to buy them?

BluD · 8 May 2016 at 11:40

I wouldnt buy any until youve tried the case fans that come with the case, they might be just fine for you.

Telecaster · 8 May 2016 at 12:24

There really should be a sticky for this, it's probably the most common question asked in here.

Basically it boils down to there being no magic/silver bullet when it comes to fans, you can't have airflow and silence, airflow is a result of RPM and noise is a result of RPM so pick what you want and try to strike a balance.

There really is no need to spend £15 on a single fan that is marketed as silent, good fans that can be run slow enough to be silent can be had for £3-5 each, the key is not running them so they get noisy but having enough airflow, this is something only you can test and not something someone can answer for you.

Disco_P · 8 May 2016 at 18:49

The above post should be a sticky.

doyll · 8 May 2016 at 20:08

Well design airflow is near silent or near silent. There is absolutely no reason for a system to be noisy in order to have good airflow. Here is a link to a basic guide to setting up good cooling and airflow.
https://forums.overclockers.co.uk/showpost.php?p=26159770&postcount=7

robalexhall · 8 May 2016 at 21:27

I should think either if those would be fine. The phantek isn't a "silent" case with noise dampening so you will be hearing broadband fan noise so the fan quality isn't such a big deal, and the fractal fans I read good things about plus case has a fan controller anyway.

My experience is with a corsair dampened case (assume fractal is similar) which while the case itself does a good job at cutting intensity it is selective and the cheapo corsair fans are annoying at just the frequencies the case doesn't block so well, I replaced them with noiseblockers after trying noctua.

Fans are all different, noctua are silent at low rpm but not that great otherwise, noiseblicker tick v quietly but otherwise superb... corsair bundled fans shriek like a banshee...

Last thing silent is relative. I have my system at 23dba with case fans 700rpm, I still don't call that silent. Its inaudible during the day sure but I wouldn't sleep with the pc on at night.

BluD · 8 May 2016 at 21:43

Shingyboy said:
What sort of fan software do you use? Do I have to buy them?

I use Speedfan m8, its a free download. Works really great with the phanteks fans and controller.

With the weather were having atm i dont think many people will be aiming for silence, my fans dont even turn on untill my loop hits about 35 degrees but even at idle theyre starting to come on every now again.......its too damn hot

Telecaster · 8 May 2016 at 22:29

BluD said:
With the weather were having atm i dont think many people will be aiming for silence, my fans dont even turn on untill my loop hits about 35 degrees but even at idle theyre starting to come on every now again.......its too damn hot

Current weather has made barely any change to my rig, less than 5 degrees on CPU and GPU, noise, or lack of it, has stayed the same.

Shingyboy · 9 May 2016 at 02:12

If I have the option in any case is it better to have 2 140mm fans over 3 120mm fans?

BluD · 9 May 2016 at 06:38

Telecaster said:
Current weather has made barely any change to my rig, less than 5 degrees on CPU and GPU, noise, or lack of it, has stayed the same.

All that means is your room has gone up by less than 5 degrees

, were not all that lucky.

Shingyboy said:
If I have the option in any case is it better to have 2 140mm fans over 3 120mm fans?

3x120 is generally better if you can get it in my experience, its not only more rad space but you have more options for static pressure fans, but it all depends on the case you get, some cases are more suited to a 280 rad over a 360. Just have a look at the water cooling options on the case specs.

doyll · 9 May 2016 at 10:28

Shingyboy said:
If I have the option in any case is it better to have 2 140mm fans over 3 120mm fans?

I use 140mm fans whenever possible. Most newer cases are more optimized for 140mm than 120mm fans. Beyond that 3x 120mm vs 2x 140mm is pretty much a toss-up.
2x 140mm fans have an airflow area of about 300sq cm.
3x 120mm fans have an airflow area of about 300sq cm.

140mm fans spin a little slower for so slightly quieter
120mm fans not only spin a little faster but 3rd fan adds 2dBA more noise.

I would post a basic chart of sound level increase to number of same fans in use, but OcUK rules do not allow posting images from other sources so I would have to first upload it to an image host before I could load it .. not worth the hassle to me.
Basically:

1 fan = 0dB increase
2x fans = 3dB increase
3x fans = 4.8dB increase
4x fans = 6dB increase

But don't think the sound from the fan is your only source of noise. Grills, filters, fins, cables, HDD cages, etc. all add noise .. so each fan added increases overall noise level of system.

Hagar · 9 May 2016 at 10:30

Shingyboy said:
If I have the option in any case is it better to have 2 140mm fans over 3 120mm fans?

2 x 140mm fans would normally be quieter.

Fan performance will be restricted by the grille or radiator that it is trying to pull or push air through. Suction (pull) is less affected by restrictions than delivery (push).

One thing to try if the case has standard molex connectors with non PWM fans is to run off the +5V and + 12V pins providing a potential difference of 7V rather than 12V. This will reduce the rpm and provide a quieter fan profile.

Telecaster · 9 May 2016 at 11:22

BluD said:
All that means is your room has gone up by less than 5 degrees , were not all that lucky.

That 5 degrees is on the max temp I see, my room has gone from 13-15 degrees to 23-24 degrees because it's a loft room.

As I type room temp is 22c and CPU is idling at 30c passively cooled, no fans.

doyll · 9 May 2016 at 11:43

nkata said:
Suction (pull) is less affected by restrictions than delivery (push).

Physics disagree with you. While ability depends on fan design, most fans push air at least as well if not better than they pull air. But there are several other variables involved as well.

BluD · 9 May 2016 at 15:46

Maybe he means volume wise rather than performance wise. Yeah i remember reading about that, it was thought for years that pulling through a rad was better as you dont get a dead spot in the middle, im guessing sumone tested this without using a seal on the fan so all the air just shot out around the edges, then someone actually locked into it and found pushing was better, by a tiny amount mind so i would still say just use which ever methods makes it easier to mount the rad.

What 360 rads you using doyll? Mine are the older ones that do have a small gap between the fans than needs sealing but it does give you a little more rad space, im getting more like 450cm rather than 300, do yours have big overhangs either end or summat?

doyll · 9 May 2016 at 16:47

Other things to keep in mind about improving fan performance and lowering noise levels:

10-20mm sealed spacer between fan and radiator / cooler is a no-brainer that not only even out the airflow, but give a significant noise reduction. 20-40mm is usually even better.
Obviously, a seal between fan and cooler/radiator is a no-brainer, but rarely done.
Removing case grill .. you got it, no-brainer. Case grill mesh typically block 30-60% of airflow area, especially front grills.
Most visible vents on cases have less than 40% airflow area than the fan they supply.
Bottom vents are almost as bad because of distance between case and what it sets on.

Quartz · 9 May 2016 at 17:01

The best way is to minimise your need for fans in the first place. With the correct case and CPU cooler, you may only need the fan on the GPU. Failing that, remember that the larger the fan, the more air it will shift for the same RPM.

doyll · 9 May 2016 at 17:06

Quartz said:
The best way is to minimise your need for fans in the first place. With the correct case and CPU cooler, you may only need the fan on the GPU. Failing that, remember that the larger the fan, the more air it will shift for the same RPM.

Please elaborate. It sounds like you are talking passive case and CPU? It that is true, there are also passive cooling GPUs. But system speed (CPU & GPU) would both be severally limited by being completely passive because more powerful / faster systems generate more heat resulting in the need of fans.