Given the sheer size of the heat spreader on Threadripper CPUs there are, understandably, concerns at how to correctly apply thermal paste for best possible heat transfer. I understand that under the heat spreader, having seen one that has been delidded, there are four modules, two of them being dummies. Would this not lead to the areas of the heat spreader over the active modules being somewhat hotter than the areas over the dummies? I understand that the active ones are diagonally arranged but there is no way to tell which way from the heat spreader.
What if the Threadripper heat spreader was segmented, something like a chocolate bar? (How thick is the heat spreader?) If there was at least one groove across the CPU (or two, dividing it into four) this would help to guarantee an even and effective spread of thermal paste over the whole surface area - one good blob of thermal paste on each section of the heat spreader with the groove(s) allowing for elimination of air and excess TP. Tests have shown that it is important to get a full coverage of thermal paste across whole of the heat spreader, right to the corners, for maximum cooling.
In the past it has been said that the less thermal paste you use between the CPU and the cooler the better for heat transfer. On a large area such as with the Threadripper, I would guess that the thickness of the thermal paste would naturally be thicker when applying enough to guarantee full coverage but with a segmented design it could be thinner and more effective.
Something to look at?