My quest to get a 120mm fan on the NH-L9x65

stratuh · January 5, 2019

I'm not a fan of LEDs or RGB. I keep my PC at eye level on my desk and LEDs just kill my eyes. I even unplug the power LED from my case because it's annoying. The only LED I'll concede to sort of digging is a very dim CPU fan LED.

This brings me to my quest: I'm a huge Noctua fan. Partly because my friend was one before me (he had an NH-D14) and because I really like my NH-L9x65. The temperatures are great and the noise is low. My sentiment is not an uncommon one judging by the numerous LTT videos I've watched on coolers and fans.

I'd love to get some RGB up in there, something I can control with RGB Fusion. Phanteks makes an LED ring thing that fits over a 120 or 140mm fan, but the L9x65 only takes a 92mm fan. Or does it? Could you fit a 120mm fan on there? Would it be better performance for cooling and noise? I'd sacrifice a degree or two to get one of the LED rings on it but I'd wager it would be cooler anyways versus the 92mm (correct me if I'm wrong). I figure it would be equivalent or better CPU cooling, and it would cool the VRMs around the CPU which the 92mm wouldn't have done as well.

The L9x65 comes with a 92mm fan that's 14mm thick. Mistake one was I ordered a 120mm fan which was 25mm thick, also from Noctua. Noctua fans have little holes on the top and bottom for fan clips, and using the L9x65 clips on the holes furthest from mobo doesn't clear the fan. 25mm is too thick. Using the ones closest to the mobo, it's too much clearance, the fan floats maybe 5mm from the heatsink.

So I ordered their own 120mm fan that was thinner: it's 15mm. It doesn't have those same holes, and using the mounting holes a) stretches the fan clips to their limits and b) obscures where the LED ring would screw in. I drilled holes roughly where the 92mm holes would sit, and it just barely doesn't work. For the 92mm fan, the clips go perfectly perpendicular from the fan face down to the heatsink, but for this 120mm fan, the angle is more. It doesn't need to go down at a 90deg angle, it's closer to 120deg, sacrificing clip length thus it doesn't fit. If the fan clips were maybe 3 to 4mm longer, it would work, though. I've attached what I mean roughly about the angles.

I didn't want to destroy these clips in case I was wrong, so I decided for now to put the 92mm fan back on. Perhaps I'd have to get different fan clips, I know they're different for the D14 or D15.

What are your thoughts? Stupid pursuit? Would a 120mm fan cool better or worse here? I've already spent around $60 in this endeavor but I'm determined for lack of a better word.

Imbellis · January 5, 2019

I've done this whole thing before and ended up with a pretty good result. The 120mm fan cooled considerably better than the 92mm fan that came with the L9x65.

The stock fan brackets didn't work for me either. I used copper wire to pull through the mounting holes - connecting to the lip where they would usually mount. It's been running for about a year on this config and I've had zero problems.

I really recommend adding the 120mm fan on with wire before mounting the heatsink to anything. It makes it much easier.

Here's another MS Paint drawing of how I did it. The wire is grey in this example. (120mm x 25mm fan connected to L9x65 via wire)

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stratuh · January 5, 2019

47 minutes ago, Imbellis said:

I've done this whole thing before and ended up with a pretty good result. The 120mm fan cooled considerably better than the 92mm fan that came with the L9x65.

The stock fan brackets didn't work for me either. I used copper wire to pull through the mounting holes - connecting to the lip where they would usually mount. It's been running for about a year on this config and I've had zero problems.

I really recommend adding the 120mm fan on with wire before mounting the heatsink to anything. It makes it much easier.

Here's another MS Paint drawing of how I did it. The wire is grey in this example. (120mm x 25mm fan connected to L9x65 via wire)

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I didn't even think of making my own clip! I'll give it a go for sure. I have a slew of different Noctua fans and held them against the heatsink to at least approximate the temps:

Baseline 92x14mm = 30c idle, 53 load

120x15mm = 32c idle, 52c load

120x25mm = 30c idle, 51c load

I'm sure it'd be somewhat improved were my case closed up and it fastened snugly. I'll pick up some copper wire later to see what I can come up with.

stratuh · January 5, 2019

I ended up getting some 16ga steel wire and tried to mount it that way: no dice. I can get it there but it's hanging and the weight of the fans makes it way off center. I wouldn't be comfortable with it like that unfortunately.