Expansion cards with PCIe 2x interface

PCIe 2x

— connection via PCIe interface using 2 lanes (data 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 this version of PCIe and the larger the connector required. A component with fewer lanes can be connected to a connector with more lanes, but not vice versa; thus, a controller with this interface can be connected to PCIe 4x, 8x, and even 16x slots.

As for 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, 2 lanes offer about 2 GB/s and about 4 GB/s respectively; this is sufficient for expansion cards, but insufficient for RAID controllers (see "Type").