Question NH-D15 underperforming?

[Vaqxai]

Hello,
Today I mounted an NH-D15 with a single fan in the middle on my Ryzen R7 5800 X3D. I applied thermal grizzly kryonaut onto the CPU as it's what I had lying around.
The Noctua manual said to apply the paste to a AM-4 CPU using a five-dot pattern with one larger dot in the middle. However, I applied the paste manually with a spatula over the whole CPU as it's what thermal grizzly recommends for that specific paste, and what I heard on this forum is correct for higher density pastes such as kryonaut.
I also used a paper towel for cleaning up the heatsink and the cpu as I did not have a good cloth at hand, and this might've introduced particles into the system, I did however visually check it and it looked ok.

The temps are "Fine" meaning 40-50C idle and 75-85C under load, BUT I do have spikes up to 90C which is a thermal throttle/limit/cutoff on this particular processor. The cooler is in my opinion not warm enough (it is somewhat warm) to the touch, and much colder than the GPU cooler.
I am wondering what this might be caused by, and considering options like:

• Uneven mounting pressure (I did the screws according to the Noctua manual, until I met resistance)
• Bad thermal paste distribution (Should I have done it as the Noctua manual said?)
• Uncured thermal paste/bad paste?

Anyhow, I do have Arctic MX-4 which just arrived, so if that might help I could just change the grizzly for that. Let me know what you think.

 

[COLGeek]

Before doing anything else, make sure you have the proper spacers in use and that you have fully tightened the cooler to the CPU.

Are you overclocking your CPU?

 

[Vaqxai]

Before doing anything else, make sure you have the proper spacers in use and that you have fully tightened the cooler to the CPU.

Are you overclocking your CPU?

I am using the spacers (you mean the gray plastic supports?) that were the only ones included with the mounting kit NM-AM5/4-MP83 which was the one dedicated for my socket and CPU cooler model. I tightened both the mounting kit screws and the cooler screws according to cooler manufacturer spec (it says 0.6Nm) but as I don't have a torque wrench, I did it according to the manual (tighten manually until resistance is met).

Not doing OCing at the moment but may consider it if temps are good enough.

 

[COLGeek]

I tighten until they no longer turn. Been using Noctuas for many years. If not fully tightened, it will decrease the cooling performance.

 

[Vaqxai]

Tightened until I no longer could, idle now is 39-40C, very stable.
Under load the temperature is stable around 60-70C, with the median being 64C

Huh, they only had like 1/8th rotation left to go, I did not expect that to do anything honestly

 

[COLGeek]

Tightened until I no longer could, idle now is 39-40C, very stable.
Under load the temperature is stable around 60-70C, with the median being 64C

Huh, they only had like 1/8th rotation left to go, I did not expect that to do anything honestly

Understood. Funny how that little bit matters, but as you have experienced, it does.

 

[Paperdoc]

VERY interesting tale, and sure to be of use to others with similar issues. Thanks for posting.