| Supply rail | M.2 Rev 4.0 | M.2 Rev 5.0 v1.0 | |-------------|-------------|-------------------| | 3.3V (pins 74, 72, 4, 2) | 2.5A max | 3.0A max (9.9W) | | 3.3Vaux (pin 71) | 0.5A | 0.5A (unchanged) |
The higher current allowance for 3.3V accommodates PCIe 5.0 controllers (e.g., enterprise NVMe SSDs) with increased logic and signal conditioning circuitry.
It is critical to note that M.2 Rev 5.0 supports only PCIe 5.0 signaling (NRZ). It does not support PCIe 6.0's PAM4 modulation. The industry is already working on M.2 Rev 6.0 to handle 64 GT/s, but that likely requires a new connector key (M.2 slots may finally evolve beyond the current 75-pin design). pci express m.2 specification revision 5.0 version 1.0 pdf
No discussion of the Rev 5.0 M.2 spec is complete without addressing heat. The document dedicates an entire chapter (Chapter 7: "Thermal and Mechanical") to this issue.
At 32 GT/s, signal loss over the short M.2 trace (approx. 3 to 8 inches) becomes dramatic. The new spec mandates stricter insertion loss budgets and crosstalk limits. For the first time, Rev 5.0 introduces mandatory requirements for SMT (Surface Mount Technology) capacitors on the module's high-speed lanes to combat resonance. | Supply rail | M
The release of the PCI Express M.2 Specification Revision 5.0, Version 1.0 marks a pivotal inflection point in high-speed interconnects. As the industry transitions from PCIe 4.0 to 5.0, the M.2 form factor—the dominant standard for client-side solid-state drives (SSDs)—faces its most significant physical and electrical engineering challenges to date.
While the specification maintains the physical footprint that has become ubiquitous in modern computing, the underlying electrical architecture has been fundamentally overhauled to support raw data transfer rates of 32 GT/s (gigatransfers per second) per lane, effectively doubling the bandwidth of the previous generation. Warning: Be cautious of PDFs circulating on file-sharing
The specification details new Phase 2 and Phase 3 of link equalization. An M.2 Gen5 SSD must support:
Warning: Be cautious of PDFs circulating on file-sharing sites. Many are outdated (Rev 3.0 or 4.0) or deliberately malformed. Always verify the hash with a standards body.
PCIe 5.0 chipsets and SSDs run significantly hotter than previous generations. The M.2 Rev 5.0 spec introduces: