ManicSouL
I'm having trouble finding a CPU air cooled heat sink that will not hit the VRM heat sink and fans assembly of the X299 DARK EATX motherboard. Hopefully someone on here knows of one that will fit and would prefer it with at least 120mm fans. Also will not use a AIO water cooler.  Thanks 
 
CPU will be i9 7940x

I take it you are going to run it with the stock Intel boost and not OC

If I go to liquid cooling, than it will be a full liquid system the works and I do not have the cash to dish out for that at the moment. Nothing at all against AIO, just not me. 

I am running a Noctua NH-D15S with a single fan on the X299 with a 7940X (stock).  Using E-Fleet CPU core temps were reported to run at idle between 22 -25 degrees C, with a CPU temperature of 24 C.  I have not looked during regular use, but will update to post temperatures on the stress test.

I was looking at the Noctua NH-D15S, but from my pixel counting I did not think it would fit the X299 Dark EATX?

Thank you and the other for their input and time.

GGTV-Jon

saberwalk
It does, with very little room, and you lose the first PCIe slot.  Take a look at the picture for my ModsRig.  When selecting my components, I read a lot on AIO's and found that there were concerns about reliability and effectiveness.  I did not run across the one mentioned above so cannot comment on it.  Uniformly, the Noctua was praised, so that is what I went with.  Like you, I want to go to a liquid cooling solution down the line, but am taking it slow. Also, just ran 3D  Mark TimeSpy and the highest temperature hit during the test was 54 C.  

Sorry to take this a little off topic but it might be relative to the OP if he uses Saberwalks setup
Saberwalk I just looked at your mods rigs pictures. Have you confirmed that the PE2 slot you are using is switching to PCIe x16 when under load?
According to the manual PE2 is an x8 signaling slot that shares lanes with PE1. You would have to use PE4 as the next available x16 slot

Thanks @GGTV-Jon, The email I got said use. So, I took a look at the enlarge photo this time and Saberwalks has the heatsink mounted 180 out of sync. With the short offset on the topside of the motherboard.

Yes, that is because I used the offset to clear the VRM fan assembly at the top.  As I recall, I tried the other orientation first, but the clearance was not good.  The only to keep slot 1 open would have been to turn the orientation 90 degrees but then I would have a vertical airflow and did not want that.

saberwalk
Yes, that is because I used the offset to clear the VRM fan assembly at the top.  As I recall, I tried the other orientation first, but the clearance was not good.  The only to keep slot 1 open would have been to turn the orientation 90 degrees but then I would have a vertical airflow and did not want that.

I have thought about going horizontal with a Thermalright Silver Arrow ITX-R or going vertical and shaving 3-4mm off the PCIe side. Turning it horizontal would not be bad idea cause hot air always rises, unless you don't have any fans on top.

Okay, I believe that I have found my own answer. The "Thermalright -  Le Grand Macho RT" will fit from my calculations and pixel counting. But waiting to hear back from Thermalright, also heard back from Noctua and they confirmed that most of the heatsinks that they had listed as compatible with the X299 Dark are not. Noctua has fixed their compatibility list to reflect that.

I was nervous as well with my X299 Dark build. I went all EK on my stuff, not a single drop of leakage with their current fittings and soft tubing. Hopefully their fittings for their Petg to works as well.

Well heard back from Thermalright early this morning and here is what they suggested. "Le Grand Macho RT doesn't fit on this motherboard, I will suggest you install the AXP-FULL COPPER on this motherboard or AXP graphite copper on this high-end motherboard as well." This is so far what I have on the AXP-100 Full Copper.  HERE
Or just search for Thermalright AXP 100 Full Copper then. 
 
But I'm not going to use it, especially with a 180 TDP. I still might buy the Thermalright Le Grand Macho RT and see what modifications need to be done. 

SimonOcean
The BeQuiet Dark Rock 4 Pro is listed as compatible and their chart usually says if any slots are blocked. For the Dark it just says "Compatible". I've not tried it myself (I am on custom water loop) but it should be sufficient to cool your i9 so long as you don't overclock.
 
Similarly, the biggest Noctua should be sufficient - as it is for the Threadripper and is just as effective as many AIOs.
 
But note that I say sufficient, rather than ample. Overclocking, particularly on something like HCC i9 changes things considerably and in this case you would be looking at delidding and water. 

Thanks for the info, personally I don't think it will fit, but I will drop them an email to see. Cause looking at the dimensions of the Dark Rock 4 Pro from the front view the width of the heat pipes is 109.6mm. Since the Lga 2066 uses the same ILM as the Lga 2011 it also shares the 101mm safe zone (the white line square) around the socket. That means the base of the VRM is 50.5mm from the center of the CPU, which is 4.3mm of interference. Yeah, I already had to have Noctua change their compatibility with a number of there coolers.
 
There is something that you or anybody could do to help my search since you own the X299 Dark and it's on liquid. Could you tell me looking straight at the VRM Heatsink on the socket side is it perpendicular to the motherboard or is it angled away from the socket? 
 

Thanks, that is a lot of help, especially the picture. By perpendicular, I meant if you cut the board in half and look at it from the side from the base of the motherboard to the top of the heatsink is straight up and down. So from GGTV-Jon's picture, I can see that it is and the fans are set back a little but did notice middle has a bulge toward the CPU some. 
Then 2 days ago I found out about Intel's 9th Generation like the i9 9940x and they are soldered which will help with cooling. As I was going to get Der8auer's Skylake-X Direct Die Frame cooling bracket to help with the cooling for the i9 7940X, now I will wait for my chance to get an i9 9940X.