Alphacool Core AM5 Performance Kit + Alphacool Core 1 + Lapped 9950x with Thermal Grizzly lapping tool

[veryetti1]

Hello everyone!

I am in the process of putting together a custom loop build. My setup: Ryzen 9 9950X + Alphacool Core 1 + Alphacool Core AM5 Performance Kit (Offset) + Thermal Grizzly AM5 Contact & Sealing Frame (TG-CSF-AM5).

I am planning to lap the CPU using the Thermal Grizzly Lapping Tool, removing up to 1.6 mm of material from the IHS. Instead of standard thermal paste, I will be using a Thermal Grizzly KryoSheet (33x33mm). Because the sheet is electrically conductive, I need to ensure the mounting pressure is absolutely perfect so it doesn't slip over time.

My question is about the Alphacool Core AM5 Performance Kit design: Since the CPU will be 1.6 mm shorter, is there enough travel in the standoffs and mounting springs to screw the block down further and still maintain the required mounting pressure? Or will the thumbscrews bottom out on the threads, meaning I need to customize the kit (e.g., shorter standoffs or extra washers)?

Thanks in advance for the clarification!

 

[veryetti1]

So basically, I think I found the answer myself. I made a 3D model to test-fit everything, and it clearly shows that the Alphacool Core AM5 Performance Kit doesn't natively support lapped CPUs.

As you can see in the screenshots, there is a gap of approximately 1.6 mm. Because the kit is designed with strict tolerances to provide perfect mounting pressure only for the stock AM5 IHS height, the block bottoms out on the standoffs.

This means that to get proper pressure on a lapped CPU, the metal standoffs from the offset kit would also need to be sanded down/machined by the exact same 1.6 mm to compensate.

UPD: The 3D model from Alphacool 3D Viewer of the alphacool core 1 black and core 1 aurora black is wrong. Gonna try to report it to alphacool and then re-do the test fit in 3d

 

[veryetti1]

Update: I decided to double-check the dimensions and found that the official 3D model (#13443) downloaded from the Alphacool 3D viewer is actually incorrect.

According to the manual, the water block's true height is 26.5 mm. With this correct dimension, the water block sits much lower. However, with a heavily lapped CPU (-1.6 mm), there is still a gap of approximately 0.46 mm between the CPU and the cold plate.

Since the Thermal Grizzly KryoSheet is exactly 0.2 mm thick, I will still be left with around 0.26 mm gap. This means the block will still bottom out on the standoffs before applying any pressure to the KryoSheet. So it seems modifying the standoffs (or using shorter custom ones) is still completely necessary for this setup.

 

[Eddy]

Since the Thermal Grizzly KryoSheet is exactly 0.2 mm thick, I will still be left with around 0.26 mm gap. This means the block will still bottom out on the standoffs before applying any pressure to the KryoSheet. So it seems modifying the standoffs (or using shorter custom ones) is still completely necessary for this setup.

There is no gap once the cooler is mounted. Quite the opposite — if there were, there would be no mounting pressure at all. I have no idea what is wrong in your drawings, but what your program is showing is simply incorrect. Your measurements are off by more than 1 mm here.

 

[veryetti1]

There is no gap once the cooler is mounted. Quite the opposite — if there were, there would be no mounting pressure at all. I have no idea what is wrong in your drawings, but what your program is showing is simply incorrect. Your measurements are off by more than 1 mm here.

Hi Eddy,

Thanks for the quick reply!

I completely agree with you — with a stock CPU, the mounting pressure is perfect and there are no gaps.

However, please note that my 3D model and my question are specifically based on a custom setup where the CPU IHS is lapped down by 1.6 mm (and using a AM5 TG Contact Frame to hold CPU).

Since the processor is physically 1.6 mm shorter than standard, my concern is that the water block will bottom out on the stock Alphacool standoffs before it can apply any pressure to the lapped CPU (or the 0.2mm KryoSheet. But anyway - I'm gonna try thermal paste first).

Did you consider the -1.6 mm lapping in your reply, or does the mounting kit actually have enough spring/thread travel to compensate for a CPU that is 1.6 mm thinner?

 

[Eddy]

Okay, then I misunderstood the original question. If you have lapped 1.6 mm off the IHS, you will not be able to use the Core cooler. The standoffs and mounting screws are designed exactly so that you tighten them fully and then get the correct mounting pressure and pressure distribution on the IHS. But if you have removed 1.6 mm from the IHS, you will no longer be able to generate any mounting pressure at all. In that case, it does not matter what you place between the IHS and the cooler — the cooling performance will be incredibly poor.

This will not work properly in any reasonable way with any of our current coolers.