Bottom line: Enthusiasts have been delidding and lapping processors for years in an effort to squeeze every last bit of performance out of their hardware. Doing so is a risky proposition but it can pay dividends if you know what you're doing.
Intel's Core i9-9900K is quickly developing a reputation for running on the warm side. Steve noted as his review of the chip and others have also picked up on it. Curious to get to the root of the cause, extreme overclocker Roman "der8auer" Hartung recently popped the heatspreader off his i9-9900K for a closer look.
der8auer discovered the chip does indeed use a soldered thermal interface material, or STIM, as many had expected. He additionally got ahold of a retail 9600K which also ran a bit toasty. After delidding this chip, he learned that it is an eight-core die and is the same size as the 9900K, just with two cores disabled.
Upon further inspection, it was also discovered that the PCB and the chip is physically thicker compared to the 8700K. What would happen if you were to shave some of that thickness off the top of the die? In theory, the thermal conductivity should improve... and that's exactly what der8auer did.
Delidding a brand new chip is risky business in itself but taking the bare die to sandpaper is next-level scary. der8auer proves that there are some notable thermal gains to be had but again, this method is not for the faint of heart.