Gen4

Gen4 is a shorthand for Generation 4, a label used across multiple industries to denote the fourth generation of a product line, technology, or standard. Because it is a generic designation, Gen4 does not correspond to a single universal specification; its exact meaning varies by context and issuer.

In automotive and propulsion, Gen4 has been used to name fourth-generation engine families. A prominent example is General Motors’ Gen IV small-block V8 family, introduced in the mid-2000s, which incorporated design and manufacturing updates to improve performance, efficiency, and durability. The Gen4 designation is sometimes applied by other manufacturers to denote subsequent generations of engines or powertrains, with each producer attributing its own technical advancements to the label.

In computing and electronics, Gen4 most commonly refers to PCI Express Gen4 (PCIe 4.0). Ratified in the late 2010s, PCIe 4.0 doubles the per-lane bandwidth of PCIe 3.0, enabling faster graphics cards, solid-state drives, and other high-speed peripherals. Realizing Gen4 performance typically requires compatible motherboards, processors, and devices, and it has influenced system architecture and data transfer expectations across consumer and enterprise hardware.

Branding and product lines outside of these areas also use Gen4 to signify a fourth-generation design, feature set, or performance tier. Because the designation is not standardized, customers should consult specific product documentation to understand the exact capabilities associated with a Gen4 version.

See also: Generation in technology, PCIe, Small-block engine.