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[SOLVED] NH-D15 CPU Cooler Clearance Corsair 460X Crystal too narrow

A Quincy Joker

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Nov 15, 2013
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https://pcpartpicker.com/user/A_Quincy_Joker/saved/z3DYJx

Hi I need help finding a case with better CPU Cooler clearance for the Chromax NH-D15 and USB ports towards the front of the case (my cats like to reset and shutdown my PC) with Airflow as a top priority. I don’t care too much for RGB in the case as my components already have some. My main issue is the amount of clearance required to clear the Tempered Glass Panel (190.2 MM or 7.5 inches approximately) and the tall RAM spreaders. The measurement from the bare metal of the inside of the case to where the fan would end up is 200.4 MM altogether with with motherboard and CPU cooler.

PC Specs:
Corsair Crystal 460X Case
Corsair H1200i Platinum PSU
ASUS ROG X470-F Gaming Motherboard
Ryzen 7 2700X 3.7 GHz 8-Core @ 4.3 GHz OC
G. Skill Trident Z RGB 8 GB x2 3200 MHz 16-18-18-38
Chromax NH-D15 CPU Cooler (162 MM under normal circumstances aka low profile RAM)
RTX 2070 SUPER 8 GB Founder’s Edition
 

Darkbreeze

Titan
Moderator
I like Fractal Design, Phanteks, Corsair, Lian Li, Be Quiet and some of the Antec models. To be honest though, a different case really isn't the solution. I'll tell you why.

Raising the front fan as much as you have to raise it is going to cause about 20% of your airflow through the heatsink to disappear. You are not only removing about a sixth of the fan surface area which is now blowing over the top of the heatsink, which does basically nothing, but also leaving about a sixth of the hottest part of the heatsink without any direct airflow over it.

I've built many systems with no more clearance between the rear exhaust fan and the rear fan on the heatsink and didn't have any turbulence or problems. If there is any, it's likely because the rear fan that's back that is not capable of keeping up with the back fan on the heatsink and rather than sucking out everything that is being sent it's way, it's waffling and there is inversion leakage of the airflow coming of the rear fan on the heatsink.

What is the model of the rear exhaust fan?

Do you have ANY top-rear exhaust fan installed in the top of the case?

You might also want to create a low speed custom curve that remains at about 30-35% PWM up until about 55ºC and then steadily increases up to 100% PWM at 75°C, for the CPU_FAN header, and then connect that rear exhaust fan to the CPU_OPT fan header. That likely will require that you connect both CPU cooler fans to the CPU_FAN header via PWM splitter cable, if they aren't already, which I'd recommend they should be.

That will allow the rear exhaust fan to react to the same thermal diode that the CPU cooler fans react to, instead of reacting to the much slower, less responsive system or VRM thermal sensors that are normally used by the case fans. It will cause it to ramp up and down, just like the CPU fan, and that can be it's own form of annoyance, but it will stop it from being a roadblock to the airflow off the CPU cooler.
 
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Darkbreeze

Titan
Moderator
It should fit that case fine. That case supports CPU coolers up to 170mm tall and the Noctua NH-D15 is only 165mm tall even WITH the fan. There should be no need for a different case based on the CPU cooler. You should have at least 5mm clearance which is plenty.

If there is some other reason you want to change cases, then I'd be more than happy to make a few recommendations. The case isn't going to have anything at all to do with how much clearance there is between the heat spreaders on the RAM and the CPU cooler. That is more of a CPU cooler and motherboard issue.
 

Phaaze88

Illustrious
Ambassador
Your math isn't adding up:
Corsair Crystal 460X - 170mm max: https://www.corsair.com/us/en/Categories/Products/Cases/Crystal-Series™-460X-RGB-Compact-ATX-Mid-Tower-Case/p/CC-9011101-WW#tab-tech-specs
NH-D15 - 165mm: https://noctua.at/en/nh-d15-chromax-black/specification
Naked ram - 31mm
G. Skill Trident Z - 44mm: in the G. Skill memory FAQ.
The NH-D15's front fan would need to be raised a little over 13mm, for a total of 178mm, which is of course, too high to fit in the chassis that way... but where did you get 190 and 200mm from?
Have you tried moving the fan to the back of the 2nd tower as a pull fan?
 
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Darkbreeze

Titan
Moderator
Also, which slots are you trying to populate in the motherboard, because if you are using the second and fourth slots over from the CPU socket, which are the ones you SHOULD be using, then there shouldn't be any clearance issues with the D15 using Trident Z unless there is something drastically different about the memory slot placement on that X470-F than what is pretty much standard for most other full sized ATX boards.

I've used the D15 and Trident Z sticks on a number of Z series motherboards from Z170 up to Z370, and didn't have clearance issues although it WAS very tight and there would have been problems if I had four DIMMs or was using the first slot.

If you were trying to use the first slot, which you shouldn't be with only two DIMMs, then yeah, you'd have clearance issues for sure. Unless I'm off my mark, and that's possible, but isn't usually the case. Even so, with an extra 5mm clearance, you should be able to slide that fan up enough for clearance if you had to, which you shouldn't, not if the memory is populated correctly unless that X470 board has the DIMM slots much closer to the CPU socket than anything I've used that cooler on.
 

A Quincy Joker

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Nov 15, 2013
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It should fit that case fine. That case supports CPU coolers up to 170mm tall and the Noctua NH-D15 is only 165mm tall even WITH the fan. There should be no need for a different case based on the CPU cooler. You should have at least 5mm clearance which is plenty.

If there is some other reason you want to change cases, then I'd be more than happy to make a few recommendations. The case isn't going to have anything at all to do with how much clearance there is between the heat spreaders on the RAM and the CPU cooler. That is more of a CPU cooler and motherboard issue.
You’re right it should fit in my case according to Noctua’s website if the fans were exactly 165 mm tall in their intended positions. However the RAM in my system has caused me to push the fan up towards the Glass Panel to the point where I can’t even keep the panel on. There’s a significant amount of height added because of this I can show you a picture to demonstrate. The front fan is sitting at approximately 190 mm give or take while the middle fan sitting is at 165 mm as intended. The fan is already touching the RAM so I can’t push it down any further without damaging my components.
 

Darkbreeze

Titan
Moderator
What about if you move your fan to the rear of the heatsink. The D14 and D15 have both been tested at various times with the fans in the front-middle vs middle-rear and there is no discernible difference in performance. So long as there is room for the fan between the rear finstack and your rear case fan, maybe that gives you enough clearance?
 

A Quincy Joker

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Nov 15, 2013
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What about if you move your fan to the rear of the heatsink. The D14 and D15 have both been tested at various times with the fans in the front-middle vs middle-rear and there is no discernible difference in performance. So long as there is room for the fan between the rear finstack and your rear case fan, maybe that gives you enough clearance?
I’ll give it a try and see if the mobo heat shield doesn’t interfere should be less height than RAM. There won’t be an issue running a rear fan and exhaust fan really close to each other right? Someone mentioned “turbulence”? Will reply back later today.
 

Darkbreeze

Titan
Moderator
The only time I've seen "turbulence" and "whirr" with three fans on a heatsink, is if the fans do not get progressively higher in CFM capability and static pressure does not also get increasingly better or at least the same, with a higher or same CFM.

The reason for that is that if progressively there is a LESSENING in capability, then successive fans become a hindrance to fans that are further forward, creating a blockage or higher static resistance because they are now IN the air path but are moving air at a slower rate than the fan in front of them so the air has to try to go somewhere which is generally to curl out the sides of the heatsink or in some cases might actually become capable of micro stalling the fan blades on the more rearward fan.

In any case, if you have identical fans in all three locations, and so long as they are halfway decent fans with fair to good static pressure and CFM, the natural pressure resistance of the heatsink fins themselves should be enough to ensure that the next fan is not becoming a restriction, if that makes sense? This applies to dual fan configurations as well. Honestly, the only way I'd use three fans on a triple finstack heatsink is if the most rearward fan was even higher, like a 2000 or 3000rpm Noctua iPPC fan, and the rear exhaust fan was as well, AND you had a fairly decent top-rear exhaust fan installed too, so that everything coming out of the heatsink gets pulled out of the case right away and doesn't just pack in to the back upper corner waiting to get out and stifling performance and heat exchange. I just don't really think there's a need for three fans on any existing heatsink anyhow.

I think there's been some performance tests done showing that two fans offer as good, or better performance, even on dual finstack heatsinks, so long as the two fans used are capable enough and have good static pressure ratings. Also quieter with two than with three, regardless of what fans they are.
 

Phaaze88

Illustrious
Ambassador
That's right, @Darkbreeze has the 2000 IPPC fans...
I triggered it by:
-mounting 3x NF-A14 IPPC 3000s on the NH-D15S
-still had a rear exhaust IPPC 3000 behind it, and 2 above it
-the other intakes were also IPPC 3000s
-then ran Asus Realbench, Prime 95, or Cinebench R20
The strange noise was produced above 2000rpm. Lower than that, and it's not heard.

I did it for craps and giggles - I don't keep the 3rd fan on there anymore.
 

A Quincy Joker

Honorable
Nov 15, 2013
37
1
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Your math isn't adding up:
Corsair Crystal 460X - 170mm max: https://www.corsair.com/us/en/Categories/Products/Cases/Crystal-Series™-460X-RGB-Compact-ATX-Mid-Tower-Case/p/CC-9011101-WW#tab-tech-specs
NH-D15 - 165mm: https://noctua.at/en/nh-d15-chromax-black/specification
Naked ram - 31mm
G. Skill Trident Z - 44mm: in the G. Skill memory FAQ.
The NH-D15's front fan would need to be raised a little over 13mm, for a total of 178mm, which is of course, too high to fit in the chassis that way... but where did you get 190 and 200mm from?
Have you tried moving the fan to the back of the 2nd tower as a pull fan?
Sorry my math was a little off. I was trying to read my measuring tape at an angle and converting from inches to millimeters. So that could be why. Would you know of any good cases that have that clearance? I would like some good suggestions to air flow. I heard good things about Lian-Li and Silverstone. I was told to avoid NZXT cases from reading other forums and watching Gamers Nexus.
 

Darkbreeze

Titan
Moderator
I like Fractal Design, Phanteks, Corsair, Lian Li, Be Quiet and some of the Antec models. To be honest though, a different case really isn't the solution. I'll tell you why.

Raising the front fan as much as you have to raise it is going to cause about 20% of your airflow through the heatsink to disappear. You are not only removing about a sixth of the fan surface area which is now blowing over the top of the heatsink, which does basically nothing, but also leaving about a sixth of the hottest part of the heatsink without any direct airflow over it.

I've built many systems with no more clearance between the rear exhaust fan and the rear fan on the heatsink and didn't have any turbulence or problems. If there is any, it's likely because the rear fan that's back that is not capable of keeping up with the back fan on the heatsink and rather than sucking out everything that is being sent it's way, it's waffling and there is inversion leakage of the airflow coming of the rear fan on the heatsink.

What is the model of the rear exhaust fan?

Do you have ANY top-rear exhaust fan installed in the top of the case?

You might also want to create a low speed custom curve that remains at about 30-35% PWM up until about 55ºC and then steadily increases up to 100% PWM at 75°C, for the CPU_FAN header, and then connect that rear exhaust fan to the CPU_OPT fan header. That likely will require that you connect both CPU cooler fans to the CPU_FAN header via PWM splitter cable, if they aren't already, which I'd recommend they should be.

That will allow the rear exhaust fan to react to the same thermal diode that the CPU cooler fans react to, instead of reacting to the much slower, less responsive system or VRM thermal sensors that are normally used by the case fans. It will cause it to ramp up and down, just like the CPU fan, and that can be it's own form of annoyance, but it will stop it from being a roadblock to the airflow off the CPU cooler.
 
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A Quincy Joker

Honorable
Nov 15, 2013
37
1
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The rear exhaust fan is a Corsair SP 120 RGB 120mm x 25mm with a capacity of 1400 RPM 26 dBA. I believe similar to the ones on the front of my case. I currently have no top exhaust fan. That was a very clever suggestion connecting the rear exhaust fan to CPU_OPT. And yes I already have the PWM splitter connected for both Noctua fans so they can have equal speeds on the heatsink.
 

Darkbreeze

Titan
Moderator
Currently, I think my favorite case recommendation (Without going extremely nuts on the price) is the Define S2 tempered glass. It has pretty much every feature you'd want a case to have, is clean, has a PSU shroud, has great cable management, good airflow (Although it would have better airflow with a modified front panel. There IS a version with a full mesh front panel, but the mesh is designed with all kinds of weird geometric angles to it which supposedly are scientifically designed to reduce noise, but I'd like it a lot better if the mesh was just flat. I might even buy one and mod it myself like I did with my Define S.) and supports CPU coolers up to 185mm tall so if you were to do something like that it would give you about 20mm (~3/4") clearance for moving the fans. That is about the best you are going to find unless you go with a much more expensive full tower case and even then, you're probably looking at a maximum of like 193mm clearance on something like the Phanteks Enthoo Pro.

Which is a great case, but it's big.
 

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