​Check PCI Express (PCIe) Slot Capabilities

800 Series devices support up to PCIe 4.0 x16 connections and require a minimum of PCIe 3.0 x16 speeds (x8 for dual port 25G) or PCIe 4.0 x8. Some physical PCIe x16 slots are configured electrically as x8 slots. These slots have insufficient bandwidth for full performance with 100G or quad port 25G devices. The software device driver detects this situation and writes a message to the system log: 63.008 Gb/s available PCIe bandwidth, limited by 8 GT/s x8 link at 0000:xx:xx.0 (capable of 252.048 Gb/s with 16 GT/s x16 link)

If this error occurs, move your adapter to a true PCIe v3.0 x16 or greater slot to avoid performance issues.