PC Watch went ahead and got under the hood of a Core i7-6700K processor, commonly known as de-lidding. What they found was an unexpectedly small silicon, which is actually shorter in proportion to its width than previous dies found on Intel Haswell-D and Ivy Bridge-D and even Intel’s i7-5775C Broadwell processor, which has the same 14 nm process. This is because the Skylake chip has a slimmer integrated graphics core and lack of an external 128 MB SRAM cache for the iGPU.
The actual substrate used on the i7-6700K is slimmer than the one on the i7-4770K. It is 0.8mm thick compared to the 1.1 mm of the i7-4770K. The IHS (integrated heatspreader) is actually thicker so it makes up for the thinner substrate. This means that you shouldn’t run into any problems using older LGA1150 coolers on this new chip.
Intel is using a silver-based TIM between the die and the IHS. The die is actually closer to the center of the IHS than previous processors.
PC Watch actually went ahead and replaced the TIM with Prolimatech PK-3 and Cool Laboratory Liquid Pro and that produced some very impressive drops in temperatures.