Expansion cards with PCIe 4x interface

PCIe 4x

— connection through PCIe interface using 4 lanes (data transmission channels).

PCIe is the main modern interface for connecting expansion cards to the motherboard. The number of lanes affects data transfer speed on one hand, and connection features on the other: the more channels, the faster the PCIe version and the larger the slot required for it. A component with fewer lanes can be connected to a slot with more lanes, but not vice versa; thus, a controller with this interface is quite suitable for PCIe 8x and even 16x slots.

Regarding speed, it depends on the interface version: PCIe 3.0 provides just under 1 GB/s per lane, PCIe 4.0 — just under 2 GB. So, 4 lanes provide about 4 GB/s and about 8 GB/s, respectively. These are quite decent speeds, suitable even for advanced expansion cards (see "Type") — however, for RAID controllers, even such speeds are considered insufficient.