PCIe 6.0 supports 64 GT/s1 or 128 GB/s per direction on an x16 connection.2 A lot of PCI-SIG collateral claims 64 GT/s is 256 GB/s, but they include 128 GB/s in both directions when they make this statement since PCIe has always been full duplex.
The above implies that 1 GT/s = 1 Gbit/s, or each transfer is 1 bit. I don’t really understand how this works.
It is the first PCIe generation to use PAM4 signaling, forward error correction, and flit-based encoding.