Dell OptiPlex 7010 / 7020: Ethernet randomly drops to 10 Mbps until power reset

Hi everyone,

I’m having persistent network speed issues with multiple Dell OptiPlex systems — both 7010 and 7020 (SFF). After some time of usage (sometimes after waking from sleep, sometimes randomly), the onboard Ethernet adapter (Intel I217-LM or I218-LM) drops from 1 Gbps to 10 Mbps. This happens even with:

• brand new Cat6 cables

• verified 1 Gbps switches and routers

• latest Intel network drivers (from both Dell and Intel)

• Speed & Duplex manually set to 1.0 Gbps Full Duplex

• all Windows and BIOS energy-saving features disabled

• up-to-date BIOS firmware

• Windows 10 and Windows 11 (both affected)

A software-level adapter reset (via Device Manager or PowerShell) does not fix it.
The only solution that works is a full power reset — unplugging the power cable from the machine for ~10 seconds, then restarting. After that, it returns to 1 Gbps... until the issue comes back.

This is happening across multiple identical machines in my network setup, so it’s not isolated.

Anyone else facing this?

Any firmware, driver, or BIOS patch that could resolve this permanently?

It looks like a hardware-level auto-negotiation bug or voltage/PHY issue in the I21x chipset.

Thanks in advance for any help or workarounds!