Question about noctua fan choice [solved]

Hi Tek Syndicate,

I'm about to build my first computer (thanks to you guys in the build a pc section, you guys are great). However they only suggested I use the stock fan with my case (a 140mm penetrator). I want to replace it with a noctua as I have heard many great things. So I immediately hopped on pcpartpicker and looked at the reviews on amazon etc for the different noctua fans. They all seem to be fantastic but there are things I don't know. They have different indicators at the end of their names. In particular I have been looking at the NF-A14 but am not sure which one to get. They have several versions: PWM, ULN, FLX (I might be missing more).

So I did some google searches and found some info. From what I understand (please correct me if I am wrong) PWM has to do with the fan automatically regulating it's speed based on temperatures from inside the case. ULN is basically factory-set at low speeds for quiet operation. FLX is factory-set at higher speeds for moving more air.

That's all well and good, but not what this is about. I want to know what you think is best for my current computer layout:


Intel Core i5-4670K 3.4GHz Quad-Core

Noctua NH-L9i 57.5 CFM (cpu cooler)

Asus Maximus VI Impact Mini ITX LGA1150

Kingston 8GB (2 x 4GB) DDR3-1600

Intel 730 Series 240GB 2.5" SSD

EVGA GeForce GTX 760 2GB

Silverstone FT03B-MINI (Black) Mini ITX Tower

Silverstone 450W SFX12V (PSU)


Right off the bat I want to get the ULN, I like things quiet, and I've seen a few reviews that people using the FT03-mini have used the ULN (although they didn't specify what parts they had). I would like to know what you guys recommend and why.


Thanks for the help in advanced



 "PWM has to do with the fan automatically regulating it's speed based on temperatures from inside the case."

I would get one of these. I have NO experience with Noctua fans, but I have heard that they regulate themselves very well from Linus, and a bunch of other people. I wanted to buy some for my NZXT Phantom 410, but the fans are quiet and efficient enough. So, if you do go with this one, read some reviews and watch some videos first!

Here's a link for one. 22 people have reviewed it and all gave it 5 stars

it depends on where you want to put the Noctua fan  is it for a rad. or for air flow ?

I'm currently using an FT03-mini case ( and plan on only using air, no rad. In this case there is only 1 case fan (140mm penetrating fan) and one low-profile cpu fan. I want to replace the stock 140mm penetrating fan with the noctua fan. The reason I ask if because I don't have enough experience to know which fan will sufficiently keep my computer cool while at the same time getting the most quiet configuration I can.

Get the FLX.  They all come with a ULNA (ultra low noise adapter) and they are all PWM.  The FLX are designed to work really well on radiators and through HDD cages, but compared to the NHA (high airflow) they move just about as much air.  For 9/10 choices those are the go to fans.  I have 3 in my case, all silent, even without the adapter, really really like them.

Sounds great. I'll go for the FLX. I have two questions.

One: Why make different versions if they all can do ULN and PWM?

Two: How does the ULNA work? Does it basically send a signal to the fan (bios?) and tell it to run at lower rpms?

Just curious and thank you for your help.

The Ultra Low Noise Adapter is an extra piece of cable that limits the currant and forces the fan to spin slower. Where as the Ultra Low Noise fans are built to be slow and are usually slower and quieter than the regular fans with the adapter.

The are built for the ultimate in quiet but are more for circulating air steadily rather than forcing pressure through radiators. Perfect for a passively cooled rig that just needs some fresh air, like a media steaming box of quiet set top box style PC for movies. The FLX gives you the choice the ULN does not.

Thank you sir. This thread is solved!