Upgrade plan available, but hardware limitations apply.
Upgrade plan available, but hardware limitations apply.
I encountered an unusual situation with my Intel X520-DA1 setup. When using DAC to connect to the switch, most tests ran smoothly until iperf3 retries started appearing. I couldn’t locate the complete height bracket after upgrading the server in a larger case, so I resorted to using the ASUS card that was failing in Windows. The rest of the details are already covered. The X520 seemed to slow down the switch even when idle, and no further iperf3 attempts were needed. Speeds became more consistent, and the network felt much more responsive—just by swapping the NIC on one client. I switched the DAC for a 10G-BASE-T SFP+ module and kept the ASUS card in my server. Interestingly, this same card would crash in Windows 11 if I downloaded something. The Linux driver also shows temperature monitoring, staying below 60°C so far; in contrast, another Linux box with the same card reached 80°C and needed better airflow. The weirdest part was discovering a loose fibre adapter on the switch. It made the switch unresponsive to any clients, even those not connected via that port, though packets continued to pass. Network gear can be quite unpredictable.
It's really odd how tricky it is to get everything up and running. You seem like you need to understand the basics to make it work.