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Fix Guide

How to Fix Dual 2.5G Ethernet (LAN) Disconnects and Speed Issues on the Minisforum UM890 Pro

Device: Minisforum UM890 Pro · Minisforum Added

Causes

  • The UM890 Pro is equipped with dual Intel I225-V (or I226-V) 2.5GbE controllers — these Intel 2.5G chipsets have a well-documented hardware bug known as the "I225-V PCH 2.5G disconnect issue" where the link drops and re-negotiates repeatedly under moderate to heavy network load (1 Gbps+ sustained throughput), particularly on the I225-V rev 2 and I226-V rev 1 stepping. This manifests as periodic 3-10 second network freezes followed by reconnection
  • Energy Efficient Ethernet (EEE) / Green Ethernet negotiation — by default, the Intel 2.5GbE controllers enable IEEE 802.3az Energy Efficient Ethernet which aggressively puts the PHY into low-power states during brief idle periods. On the UM890 Pro, the transition between low-power and active states causes the link to drop and re-negotiate at 100 Mbps instead of 2.5 Gbps, requiring a full cable re-plug to restore full speed
  • The Intel 2.5G controllers have an incompatibility with certain switch chipsets, particularly Realtek RTL8125B-based switches and older unmanaged Gigabit switches that implement 802.3bz (NBASE-T) incorrectly. When the UM890 Pro auto-negotiates with these switches, it may settle on 1 Gbps or 100 Mbps instead of 2.5 Gbps, even with a Cat6 or higher cable
  • Cat5e or poor-quality Ethernet cables are insufficient for 2.5 GBase-T at full distance (100 m) — the UM890 Pro's I225-V controllers require at least Cat6 cable for stable 2.5 Gbps operation. Cat5e cables often pass certification for 1 Gbps but fail at 2.5 Gbps due to higher crosstalk and insertion loss, causing intermittent link flaps, high CRC error counts, and speed downgrades
  • IRQ (Interrupt Request) conflicts or offload engine crashes — the Intel I225-V driver on Windows uses the "Intel® Ethernet Controller I225-V" NDIS driver which enables hardware offloading features (Large Send Offload, TCP Checksum Offload, RSS). On the UM890 Pro with the Ryzen 8945HS platform, these offload engines can crash when processing fragmented packets, causing the network adapter to disappear from Device Manager until a full system reboot

How to Fix

  1. Update the Intel Ethernet driver to the latest version from Intel's support site or the Minisforum UM890 Pro product page. The Intel 2.5GbE driver versions 2.1.4.4 and newer contain critical fixes for the I225-V/I226-V disconnect bug. Open Device Manager → Network adapters → right-click Intel® Ethernet Controller I225-V → Update driver → Browse my computer → point to the downloaded driver folder. Repeat for the second LAN port
  2. Disable Energy Efficient Ethernet: in Device Manager → right-click the Intel 2.5GbE adapter → Properties → Advanced tab. Find Energy Efficient Ethernet and set it to Disabled. Also find Green Ethernet or Power Saving Mode and set to Disabled. In the Power Management tab, uncheck Allow the computer to turn off this device to save power. Repeat for both LAN ports
  3. Disable interrupt moderation and hardware offloads that are known to cause crashes on the Ryzen 8945HS platform: in the same Advanced tab, set Interrupt Moderation to Disabled, Large Send Offload (LSO) to Disabled, TCP Checksum Offload (IPv4/IPv6) to Disabled, and UDP Checksum Offload (IPv4/IPv6) to Disabled. This shifts packet processing from the controller hardware to the CPU, which has minimal performance impact at 2.5 Gbps on the Ryzen 9 8945HS but eliminates offload-engine crashes
  4. Force the link speed to 2.5 Gbps Full Duplex: in Device Manager → the Intel adapter → Properties → Advanced tab → Speed & Duplex → set to 2.5 Gbps Full Duplex (not Auto Negotiation). This prevents the adapter from negotiating down to 1 Gbps or 100 Mbps due to EEE transitions or switch compatibility issues. If the link does not come up at this setting, your cable or switch does not support 2.5 GBase-T — revert to Auto Negotiation and troubleshoot the cable first
  5. Replace any Ethernet cables that are Cat5e or below with certified Cat6 or Cat6a shielded cables. The UM890 Pro's I225-V controllers require all four copper pairs to be properly terminated for 2.5 Gbps operation. Cat6 cables have tighter twist ratios and better crosstalk isolation. Even a 1-meter Cat5e patch cable can cause link instability at 2.5 Gbps due to near-end crosstalk (NEXT) exceeding the PHY's tolerance
  6. If using a switch that supports 2.5 Gbps, check the switch web interface for EEE settings and disable IEEE 802.3az on the switch port that the UM890 Pro is connected to. Many managed switches (e.g., TP-Link TL-SG3210XHP-M2, Ubiquiti USW-Aggregation, QNAP QSW-2104-2T) have a per-port EEE toggle. On unmanaged switches that do not allow configuration, connecting through a managed switch upstream or setting the UM890 Pro's adapter to 1 Gbps Full Duplex may be the only reliable option
  7. For Linux users: disable EEE and offload features using ethtool. Run the following commands for each interface (replace eth0/eth1 with your interface names): sudo ethtool -s eth0 wol d (disable Wake-on-LAN), sudo ethtool -K eth0 gso off gro off tso off tx off rx off (disable all hardware offloading), and sudo ethtool --set-eee eth0 eee off (disable EEE). To make these persistent across reboots, add them to /etc/rc.local or a systemd service file
  8. If network disconnects persist despite all software fixes, the Intel I225-V controller itself may be faulty. The UM890 Pro has two independent 2.5G ports — test the other LAN port to isolate the issue. If only one port fails, that controller likely has a physical defect and the unit should be RMA'd with Minisforum support. If both ports fail under identical conditions, the issue is either the connected network infrastructure (switch/cable) or a platform-level problem that requires a BIOS update to fix