cant get 5000mbps/link speed on sfp+ usb nic

[faisa7847]

root@NFPVE01:~# ethtool enx6c1ff756fa42
Settings for enx6c1ff756fa42:
Supported ports: [ MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
2500baseT/Full
5000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 5000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Link partner advertised link modes: 10baseT/Full
100baseT/Full
1000baseT/Full
10000baseT/Full
2500baseT/Full
5000baseT/Full
Link partner advertised pause frame use: No
Link partner advertised auto-negotiation: Yes
Link partner advertised FEC modes: Not reported
Speed: 5000Mb/s
Duplex: Full
Auto-negotiation: on
Port: MII
PHYAD: 32
Transceiver: internal
Supports Wake-on: pumbg
Wake-on: d
Current message level: 0x00007fff (32767)
drv probe link timer ifdown ifup rx_err tx_err tx_queued intr tx_done rx_status pktdata hw wol
Link detected: yes



Bus 002 Device 002: ID 0bda:8157 Realtek Semiconductor Corp. USB 10/100/1G/2.5G/5G LAN


root@NFPVE01:~# ethtool -i enx6c1ff756fa42
driver: r8152
version: v2.20.1 (2025/05/13)
firmware-version:
expansion-rom-version:
bus-info: usb-0000:00:14.0-1
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: no
supports-priv-flags: no



I have two nodes with similar config and all the similar output
But cant seem to get the full 5000mbps speed while testing

 

[LnxBil]

According to the negotiated speed, you have it:

Speed: 5000Mb/s

Are you refering to the throughput you measures with e.g. iperf?