SSUPD PCIe 5.0 x16 Riser Cable 200/320/440mm 32 GT/s Transmission, 64 GB/s (256 Gbps) Bandwidth GPU RTX 5090/5080 & RX 9070 XT & ITX Case Ready (PCIe 5.0 Female Reverse 440mm)

Optimal PCIe Slot Selection
Plugging the cable into a full-length PCIe x16 slot ensures maximum bidirectional bandwidth (e.g., 128 GB/s for PCIe 5.0). In contrast, using an x8 slot halves the available lanes, limiting throughput to 64 GB/s. However, actual performance depends on:
Motherboard PCIe Version: PCIe 5.0 x8 (64 GB/s) still outperforms PCIe 4.0 x16 (64 GB/s).
Physical Slot Integrity: Some x16-shaped slots have only x8 electrical contacts, as seen in older motherboards like the Z97-A.
CPU/Motherboard Lane Allocation: Multi-GPU setups may force x16 slots to split into dual x8 modes.