Hi, as far as I know from HPE Aruba documentation (various sources) the 5G Smart Rate (multi-Gigabit) ports support on Aruba CX 6400 Switch series means the support of: 5GBASE-T, 2.5GBASE-T, 1000BASE-T and 100BASE-TX modes of operation over Twisted-Pair Copper cabling.
The 5GBASE-T and 2.5GBASE-T (SmartRate) modes support both IEEE 802.3bz and NBASE-T modes of operation to maximize compatibility during deployment.
Given that, the R0X41C module (the SKU for "HPE Aruba Networking CX 6400 48-port HPE Smart Rate 1/2.5/5GbE Class6 PoE and 4-port SFP56 v2 Module") should support speed ranging from a lower limit of 100 Mbps up to the higher limit of 5 Gbps over copper (considering a supporting peer and cabling).
With regard to the 48-port 1GbE Class 6 PoE and 4-port SFP56 v2 Module (R0X40C), the 1000BASE-T ports support should mean: 1 Gbpss, 100 Mbps and 10 Mbps modes of operation over Twisted-Pair Copper cabling (the 100BASE-TX and the 10BASE-T modes both support Full-Duplex and Half-Duplex operation).
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