Completed Noctua bracket for LGA 2011 Narrow ILM


What's an ITX?
New User
Feb 20, 2024
I need one for my Project Jolokia build to mount the NH-L12 to the ASRock X99E-ITX/ac motherboard because the L9x65 would interfere with the RAM slots.

It's just two simple brackets, pretty straightforward. Am I the only one still interested in mounting Noctua heatsinks to the ASRock X99 ITX? And if anyone else is interested, what cooler would you want to use so I can check if it fits?

CAD Files:

Feb 4 Update: They're here!

The brackets are here and I've installed and test them:

The Problem

To review for those not familiar with the issue, there are actually two different mounting patterns for Intel Socket 2011-0 and 2011-3. There is the normal Square ILM ( 80mm x 80mm) on the left, and the Narrow ILM (94mm x 56mm) on the right. ILM stands for Independent Loading Mechanism and is just the fancy name for the metal retention bracket and levers that hold the CPU down.

The Narrow ILM is not something most PC enthusiasts run into though, because it's almost exclusively used on server motherboards to conserve PCB real estate. But that space savings is the exact reason ASRock used it on the X99E-ITX/ac, their crazy X99 Mini-ITX motherboard that everyone else said was infeasible.

Since no consumer heatsinks are compatible with the Narrow ILM, ASRock thoughtfully bundles a Dynatron R24 server heatsink as a backup. They also bundle a bracket to mount the Cooler Master Seidon 240V and a few other AIO water coolers. And there is a similar bracket available from Asetek's eBay store, for Asetek-based AIOs that use their standard mounting.

I don't like pump noise and I'll be flying with the rig this will all eventually go in, so I don't want to water cool. The selection of air coolers that can mount to the Narrow ILM is basically limited to server heatsinks like the R24 that the board comes with though.

And pump noise absolutely pales in comparison to the racket this 2U server heatsink can generate, with the 60mm fan maxing out at 7000 RPM! And the heatsink itself doesn't even cool that well with the CPU under heavy load, so you can actually expect the fan to reach those ear-splitting levels of noise :mad:

Noctua is my brand of choice for heatsinks and fans, and they actually do make workstation heatsinks for the Narrow ILM. But they use a different mounting system than their consumer heatsinks and I need a low-profile cooler like the NH-L12, which isn't available in the workstation line :(

Here you can see the problem with the stock Noctua 2011 mounting bars, they just are too long in this orientation. They're also too short in the other orientation, but even if they weren't, the RAM slots are in the way because everything on this board is an exercise in maximizing space efficiency.

The Solution

I'm crazy and have a poor sense of fiscal responsibility dedicated to solving problems, so obviously the solution was to make my own bracket! XD

This required modeling the NH-L12's stock mounting system (though I modeled the rest of the heatsink for good measure), convincing ASRock to send me a mechanical CAD model of the motherboard to check clearances, and then doing a 3-hour live stream where I put it all together and designed the custom mounting bar:

The actual designing of the mounting bar itself starts about 2 hours and 30 minutes into the video.

Then I made some minor tweaks, got a quote from a local sheet metal shop, and two weeks later ended up with these:

Not much to look at, but they'll do the job :)

Prep work

Here are all the necessary parts:
And I don't even need a screwdriver. The heatsink actually comes with one, 'cause Noctua is awesome like that :cool:

The reason I needed the 2011 mounting kit is that the NH-L12 has a slightly different mounting than the other Noctua heatsinks, because of these fixed mounting screws. The reason for that, is the L12 has the option for a 92x25mm fan mounted to the bottom of the fin array, and that fan would interfere with a taller mounting screw.

But also, there is a subtle difference of 0.5mm in height from the top of the CPU's heatspreader to the top of the motherboard (the stackup height) between Socket 2011-0 (as used in the X79 platform) and 2011-3 (used in X99). Even more confusingly, some X99 motherboards are still using the 2011-0 ILM, so depending on which particular X99 board you get, there could be a 0.5mm height difference that the heatsink has to account for.

To account for these small differences, and to prevent the user from overtightening the screw, the other Noctua heatsinks have spring-loaded screws. Noctua has a spacer kit for the 2011-3 Square ILM available by request, but to be safe, I opted to get the spring-loaded brackets via the NM-I2011 kit. This will prevent me from using a 25mm thick fan on the bottom, but I plan to use the upcoming slim 120mm Noctua on top anyway, so I'm not giving up anything.

Those brackets are attached to the heatsink base with two screws each, so it's a simple swap. And now my NH-L12 is equipped to deal with those pesky stackup height discrepancies.


After getting the NH-L12 prepped, the rest of the assembly is basically the same procedure as mounting to the normal 2011 socket:
  1. The 2011 standoffs are screwed into the threaded studs that are part of the ILM
  2. Place the mounting bars on top the standoffs
  3. Install the thumbscrews that hold the bars in place

Part of the reason the live stream was so long is that I did lots of prep work to ensure there was no interference with the ILM, the rest of the Noctua mounting or heatsink, and the various motherboards components.

That work paid off, and the custom brackets clear the VRM heatsink with room to spare :)


Then thermal paste is applied, the heatsink is screwed onto the threaded studs in the mounting bars, and it's done! A consumer Noctua heatsink mounted to the Socket 2011-3 Narrow ILM :)

Here it is with a FSP500-50FSPT FlexATX PSU and MSI GTX 1050 Ti low-profile card.

And from this angle you can see why the taller spring-loaded screws prevent thicker fans from fitting on the bottom of the heatsink.


Running Prime95 Blend the Xeon E5-2683 v3 I'm using peaks in the mid 70s celsius, but that's with the Noctua NF-F12 on top only spinning at 1000 RPM. I could easily get better temps, but I prioritize low noise over low temps. If it's under TJ Max I just can't be bothered to care about lowering the load temperatures.

Overall I'm very happy with how this turned out. Everything fit perfectly and now I can hear myself think when the CPU is under load :D


Unfortunately even though they were made at a local shop, I wasn't allowed to come and take pictures because apparently some of the stuff they work on is under NDA.

But they did give me the piece of sheet metal the parts were cut from, so that's neat :)

An interesting manufacturing detail we can see is the laser cutter's pierce point. When laser cutting, the beam doesn't instantly punch through the metal, it requires a bit of time to "drill" through the sheet. Once the laser pierces the sheet, it can then start moving and cutting the metal.

But as can be seen here, where the laser pierces leaves a bit of bit of melted aluminum on the bottom of the sheet. So it starts the pierce a little bit away from where the part starts, and then starts moving to cut the part out.

So I guess I have a bunch of extra mounting bars, whatever shall I do with them? :p
I cringe at opening a dead thread, but I couldn't find the option to DM you either (maybe because I just made my account here?)

Do you happen to still have any of these mounting bars? Open to selling them?