One of the most critical sections within the PDF is the thermal management section.
The (released officially on November 17, 2020) defines the physical and electrical standards for next-generation mobile and desktop expansion modules. This revision integrates the high-speed data rates of the PCIe 4.0 Base Specification into the compact M.2 form factor, effectively doubling the bandwidth available to SSDs and other peripherals compared to the previous Gen 3 standard. Core Advancements and Technical Features Pci Express M.2 Specification Revision 4.0 Version 1.0 Pdf