Note: A typical GPU slot (x16) at Gen 5 speeds offers a theoretical bandwidth of ~128 GB/s.
Bandwidth is only half the story. PCIe specifies mechanisms for low-latency communication: pcie specification
| Generation | Spec Name | Data Rate (per Lane) | Bandwidth (per Lane, Bi-directional) | Encoding Scheme | | :--- | :--- | :--- | :--- | :--- | | | PCIe 1.0 | 2.5 GT/s | 500 MB/s | 8b/10b | | Gen 2 | PCIe 2.0 | 5.0 GT/s | 1,000 MB/s | 8b/10b | | Gen 3 | PCIe 3.0 | 8.0 GT/s | ~2,000 MB/s | 128b/130b | | Gen 4 | PCIe 4.0 | 16.0 GT/s | ~4,000 MB/s | 128b/130b | | Gen 5 | PCIe 5.0 | 32.0 GT/s | ~8,000 MB/s | 128b/130b | | Gen 6 | PCIe 6.0 | 64.0 GT/s | ~16,000 MB/s | PAM-4 / FLIT | Note: A typical GPU slot (x16) at Gen