💾 Storage
PCIe Generations (4.0, 5.0)
Each PCIe generation roughly doubles the bandwidth per lane of the one before. A device only runs at the generation its slot supports, whichever is lower.
PCIe is the high-speed bus that connects graphics cards and NVMe drives to the CPU. Generation 4.0 roughly doubled 3.0's per-lane bandwidth, and 5.0 doubled it again.
Devices and slots negotiate down to whichever side is slower. A PCIe 5.0 drive in a 4.0 slot works perfectly — it simply runs at 4.0 speeds. Nothing breaks; you just don't get what you paid for.
On many motherboards the generation differs between slots. The primary M.2 slot wired directly to the CPU is often a generation ahead of the secondary slots routed through the chipset.