Raptor Computing Systems Hardware > Mod Zone
Custom cooler mount
ejfluhr:
Do you have any idea how much force you are applying down through the module to the socket pins? IBM has a target pressure to ensure even and reliable contacting across all pins for the life of the processor given certain assumptions about electrical loads (e.g. amps thru pins) and thermal cycling. It would be interesting to know if your solutions are approximately the same, or much higher or lower.
Woof:
I've no idea of the amount of force. For the design I went with the same mounted hight (via trial and error and shims) as the Noctua cooler and the EK water block on an AM5 mobo.
What I found was, for the Noctua, until I got this height and the stiffness right then the system wasn't stable. Once I got this correct (measured at the spring hight, how far they were tensioned, how the cooler sits on the CPU including getting its eccentricity right) the system was a stable and I could wobble and shake the cooler. After the Noctua's SecuFirm2 mounts I did the same for the EK Pro water block. AM5 is a 1781 pin LGA, the POWER9 Sforza is a 2601 pin LGA, and have 40x40 vs 48x48 IHS sizes (but the coolers usually have 50x50 cold plates), so they're not like for like.
The socket I used for mounting and testing the various coolers had maybe 20 mount and test cycles, trying to keep the number down (since I'd read the socket was good for very few cycles). The second CPU socket, used for all the measuring and verification, seems to have been trashed in the process (I must have eventually squashed the pins, I'll need to get my SMT stereo microscope unpacked to look). The lack of independent loading mechanism (like on the AM5) appears to have been the downfall.
For stability testing I ran this machine hard for multi-day cycles (one of my own tools that 100% loads the CPU cores with lots of maths).
Since I trashed my second CPU socket I've not been able to test both CPUs yet, I need to solve that next.
Woof:
I found the problem with my second CPU, I appear to have dropped something onto the socket and bent a bunch of pins:
https://wip.numfum.com/cw/2023-08-21/cpu2-cu.jpeg
I have a replacement mobo coming from Raptor so will get back on with this in a few weeks.
ClassicHasClass:
Ugh!
Woof:
--- Quote from: ejfluhr on August 17, 2023, 11:02:38 am ---Do you have any idea how much force you are applying down through the module to the socket pins?
--- End quote ---
I'm going to build a jig to measure this, for both the Noctua and EK options, then I can tailor the springs to make sure the force is similar to the IBM part. It'll keep me busy waiting for my replacement mobo to be delivered.
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