 This is a considerable improvement on the 25% overhead of the previously-used 8b/10b encoding scheme, which added 2 coding bits to every 8 payload bits.The overhead can be reduced further by doubling the payload size to produce the 128b/130b encoding used by PCIe 3.0 and 128b/132b encoding used by USB 3.1 and Display Port 2.0.As its scheme name suggests, 64 payload bits are encoded as a 66-bit entity.