NF-A4x10
A 40mm fan isn’t going to do much for case airflow but we do see them in systems and some external hard drive chassis from time to time.
When we received the 40mm fans, we had every intention of using them on our ASUS Z87 Gryphon in the thermal armour kit but alas the ASUS fan is a 38mm and the tolerance isn’t there to fit the NF-A4x10 frame without damaging the housing so we couldn’t test it in that application. We did test the 12V NF-A4x10 (ULN) next to the ASUS 38mm fan from the armour kit and it is a real shame that the mount wasn’t 2mm bigger because the Noctua fan made less noise and seemed to push a lot of air at the same time. This is likely due to the Noctua design where they reduced the hub diameter of the fan which allows the blades to be larger with more surface area. This means that the blades can move more air without needing to spin faster.
Being a premium fan kit, Noctua has thought about how these will be used and has included the OmniJoin Adaptor sets to allow modders to use the fans without soldering on a different connector.
Be careful when buying the NF-A4x10mm fan as there are two different versions, a 5v version that Noctua state shouldn’t be run any higher and a 12v version that can be run off of a motherboard header or MOLEX adaptor.
If you have an external hard drive enclosure or other device with a loud or defective 40mm fan, it might be worth seeing if either of these options are suitable because a $22 repair could be a lot cheaper than a total device replacement.
Like the 80mm fans, these are also suitable for pushing/feeding air into parts of your case that could use some extra cooling. Being 40mm wide by 10mm thick, the NF-A4x10 is a very compact size and whilst it isn’t silent, it is still quiet and will blow a focused flow of air across heat sinks or RAM modules. The holes in the corners of the AAO frame mean that it won’t be too hard to rig something up to position it as required. At 40mm, this little fella should also be easier to conceal but like all Noctua’s Premium grade fans, it’s still beige and brown.
What amazed us the most was that the AAO frame, fan blade geometry and bearing technology all scaled down this far from the 150mm NF-A15.
The packaging is the same size as the other fans in the premium range – which is pretty funny when you open the front flap to see a tiny fan in the middle of the packet. Major overkill there Noctua, but it does mean that there is room to list all the features on the box.
NF-A4x10 5v
The NF-A4x10 5v uses as the name suggests, a 5v input voltage. running it any higher will damage the fan. It is intended to replace noisy or broken 5v 40mm fans. The OmniJoin adaptors allow you to connect it to proprietary fan headers without the need to use a soldering iron.
Our testing of this was sadly limited – the plan to use either of these fans in our Z87 Gryphon was a FAIL due to the tight tolerance of the 38mm fan mount in the thermal armour. What we can say is that the 5v version seemed to move more air with less noise than the other 5v 40mm fan that I had around the lab. The fan used for comparison was a spare part, a previously unused generic unit without a label. It was hardly a fair contest given that the generic fan had cost around $5 and the NF-A4x10 retails for ~$22 but I know which one I’d prefer to sit in the same room with.
NF-A4x10(FLX)
The NF-A4x10 FLX is capable of operating at up to 4500rpm at 12v and 3700 with the LNA attached. There are both an OmniJoin set and a 3-2 pin adaptor included to make sure you are good to go.
The NF-A4x10 FLX is rated at 17.9dB(A) and whilst our decibel meter again struggled to get a clear reading, we could hear the pitch of the fan and it was more audible than the NF-A8 and NF-A9 series. With the LNA fitted, the NF-A4 was extremely quiet on the open test bench and inaudible from within our Node 804 chassis. I actually sat next to the NF-A4x10 FLX for a full day while working to see if it bothered me and I barely noticed it – from a distance less than 1m in the open.
Unlike the NF-A8 and NF-A9 this fan is going to appeal to a niche market but if you are looking for a 40mm fan, you owe it to your ears to get this one.
