System and method for information handling system input/output resource management

An information handling system includes a processor complex with a root complex that provides N serial data lanes, where N is an integer. The information handling system also includes boot process logic that determines that a device is coupled to X of the serial data lanes, where X is an integer less than N, determines that no device is coupled to Y of the serial data lanes, where Y is an integer less than or equal to N−X, and allocates a portion of bus resources of the root complex to the device, the portion being greater (X+Y)/N.