What does the X4 mean in an PCIe Gen X4 NVME drive?

Differences Between M2 Cards M2 Slots Keys Sizes and Types m 2 slot with pcie x4 lanes 2 PCIe NVMe drives are 'M' keyed SATA ones, however, are 'B+M' The former ensures the absolute fastest speeds The latter, however m24 slot wallet The top slot that has the heat-sink on it does use PCIe lanes If you use it your x16 PCIe slot will only use x8 speeds

m2 slot types Generally speaking, if you install an SSD in the chipset slot, you're going to see it use 2 lanes worth of bandwidth most of the time