Using only 1,22 Gbits/sec instead of 2,5 Gbits/sec

[toplap]

Iperf is showing 1,22 Gbits/sec and not 2,5 Gbits/sec. The Server is connected with a CAT 8 cable to a 2,5 Gbits LAN port on my router.
In Ookla i get 900 Mbps on proxmox and at my Comuter i get 1500 Mbps.
Can someone help me? Thanks!

driver: r8169
version: 6.8.12-9-pve
firmware-version: rtl8125b-2_0.0.2 07/13/20
expansion-rom-version:
bus-info: 0000:25:00.0
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: yes

25:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller [10ec:8125] (rev 05)

Settings for enp37s0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
2500baseT/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
2500baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
2500baseT/Full
Link partner advertised pause frame use: Symmetric Receive-only
Link partner advertised auto-negotiation: Yes
Link partner advertised FEC modes: Not reported
Speed: 2500Mb/s
Duplex: Full
Auto-negotiation: on
master-slave cfg: preferred slave
master-slave status: slave
Port: Twisted Pair
PHYAD: 0
Transceiver: external
MDI-X: Unknown
Supports Wake-on: pumbg
Wake-on: d
Link detected: yes

 

[Maximiliano]

Hello,

Is the Proxmox VE host connected directly to the router? What exact iperf incantation did you use? Did you use iperf or iperf3? Perhaps you need to run iperf with more than 1 thread to achieve full speeds.