NAS servers with PCIe expansion slot

PCIe

— universal connector for connecting internal components, currently the most popular among similar interfaces. It allows you to connect both expansion cards and drives — mostly quite advanced and high-speed SSDs (manufacturing hard drives for PCIe doesn't make sense for several reasons). Specifically in NAS servers, this interface is usually used as an auxiliary, in addition to the more traditional SATA 2 and/or SATA 3 (see relevant sections): the main set of drives is connected via SATA, and an SSD is installed in the PCIe to accelerate server performance or an expansion card that provides additional features (such as a sound card or Wi-Fi adapter).

It should be noted that PCIe connections can use a different number of lanes — mainly 1x, 4x, or 16x (this number directly affects data transfer speeds). The compatibility rule here is as follows: the connector must have no fewer lanes than the connected component. However, in NAS servers, this usually isn't an issue — they mostly use quite "undemanding" PCIe 1x cards, compatible with connectors of any number of lanes.