A Closer Look
The Core i9-7900X comes in a slim, but larger box than, say, the i7-8700K. The front features the signature "X" marking of the Core X family. Inside, you only get the case-badge and documentation, apart from the processor itself. You use your own cooling.
The Core X family is based on Intel's new LGA2066 package. This package features a double-decked fiberglass substrate and a copper integrated heatspreader (IHS) with thermal paste between the IHS and the CPU die.
The LGA2066 socket features the same mount-hole spacing as LGA2011 and LGA2011(v3), which means there have been compatible coolers for this socket for over five years now. Just make sure your cooler can handle thermal loads of up to 140W TDP.