I've tried several cables and I am pretty certain the NIC/OS is the problem. My NIC in my mobo supports 1Gbps but when connected to my homeplug (Devolo Magic 2 Wifi, deffo support GB ethernet), it always shows in KDE OS system tray icon as being connected in 100Mbps mode.
I've ran ifconfig below
enp5s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.50.2 netmask 255.255.255.0 broadcast 192.168.50.255 inet6 fe80::7285:c2ff:fec8:1023 prefixlen 64 scopeid 0x20<link> ether 70:xx:xx:xx:xx:23 txqueuelen 1000 (Ethernet) RX packets 138995 bytes 119279125 (119.2 MB) RX errors 0 dropped 142 overruns 0 frame 0 TX packets 201518 bytes 233657407 (233.6 MB) TX errors 6 dropped 0 overruns 0 carrier 2 collisions 7086
lspci -v :
05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15) Subsystem: ASRock Incorporation Motherboard (one of many) Flags: bus master, fast devsel, latency 0, IRQ 36 I/O ports at f000 [size=256] Memory at f7504000 (64-bit, non-prefetchable) [size=4K] Memory at f7500000 (64-bit, non-prefetchable) [size=16K] Capabilities:  Power Management version 3 Capabilities:  MSI: Enable- Count=1/1 Maskable- 64bit+ Capabilities:  Express Endpoint, MSI 01 Capabilities: [b0] MSI-X: Enable+ Count=4 Masked- Capabilities:  Advanced Error Reporting Capabilities:  Virtual Channel Capabilities:  Device Serial Number 23-10-c8-c2-85-70-00-00 Capabilities:  Latency Tolerance Reporting Capabilities:  L1 PM Substates Kernel driver in use: r8169 Kernel modules: r8169
Any clues as to how I can get this working in GbE mode?
ethtool enp5s0 | grep Speed
Cannot get wake-on-lan settings: Operation not permitted Speed: 100Mb/s
ethtool enp5s0 ...
Settings for enp5s0: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supported pause frame use: Symmetric Receive-only Supports auto-negotiation: Yes Supported FEC modes: Not reported Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: Symmetric Receive-only Advertised auto-negotiation: No Advertised FEC modes: Not reported Speed: 100Mb/s Duplex: Half Port: MII PHYAD: 0 Transceiver: internal Auto-negotiation: off Cannot get wake-on-lan settings: Operation not permitted Current message level: 0x00000033 (51) drv probe ifdown ifup Link detected: yes