I am considering getting/making a copper shim to bond to the Broadcom BCM2711 so I can use a much thinner thermal pad and add a little more thermal mass.
By my measurements the pad that comes with it is about 4mm but the actual depth from the shell back it is stuck on to the point the chip presses in is about 3mm. Can anyone confirm that a 3mm shim bonded to the Broadcom BCM2711 would come close but not touch the shell so I could use a .5mm pad for contact?
Also, are there other things that should also get some thermal transfer? Should the memory chip on the right or the little Broadcom chip above it get some thermal help as well? I would use thermal adhesive on the Broadcom BCM2711 but I could put appropriately sized thermal pads between other chips and the copper shim if needed. I plan on having the shim large enough to cover those regardless. I’m thinking somewhere around 30mm square would be sufficient.
If anyone knows the answers, you could save me a bit of work. Thank you in advance for any assistance.
@AlexDuan - just tagging you in case you happen to have the answers. Thank you.
I have thermal pads on all the chips but I don’t think copper shims would be necessary. I have my CM4 OC’d and if I stress test the device for over an 2 hours I can’t get the temps above 57C. The back gets warm but not HOT.
Right, it is not so much about being able to push it harder on overclock. It is about a more effective and efficient transfer of heat to the shell. The copper is going to be better than a thick pad at moving the heat across, and having a thinner pad means not having to source a thick 4mm beast. This means that frequent open and closing of the shell should not affect the pad as much, and when I do have to replace it, .5mm is much easier to find than the thick, custom pad it came with.
4mm? I bought the wrong stuff, i think the selection I bought only goes up to 2mm.
I was thinking of copper shim and some goo for mine. Here’s a trick from building engines for checking clearances. Get some modelling clay, the kind that doesn’t harden. Place a blob on each component, assemble the case. Pull it back apart and measure the thickness of the squashed areas.
I went through all this with mine and it does work well. Bought .05mm up to 3mm in .05 increments. I wish I remembered what I used so I could tell you but i went .05 grizzly pad on chip, thickest all copper heatsink I had then whatever thickness was remaining in the grizzly pad to reach the top of the back case.
I have my uconsole OCd and running pretty steady at 2.2GhZ and I have ran a pretty taxing program, AngryOxide, for several hours straight and it remains very cool. I dont know if all the work was necessary but im a nerd and it was fun.
You can check out a little glipse of it in the mega mod thread.
Unfortunately I don’t remember which thickness they were. I made them as thick as possible with still being able to have the .05 grizzly in-between the shim and back case.