Intel I226-V 2.5GbE Ethernet Controller: Specs and Support

Intel lists the I226-V as a single-port Ethernet controller in the I226 family for PC, client and tablet use. Its network side supports the NBASE-T family up to 2.5 Gb/s, while Intel’s I226 family description identifies 2500BASE-T, 1000BASE-T and 100BASE-TX operation.

That 2.5 Gb/s figure is the controller link rate, not a guaranteed file-transfer or internet speed. End-to-end throughput also depends on the other Ethernet endpoint, switch or router, cabling, protocol overhead, storage and workload. A PC containing an I226-V therefore has a 2.5GbE-capable controller, not a promise that every connection will run at 2.5 Gb/s.

Intel specifies the I226-V system interface as PCIe 3.1 and lists its speed and width as 5 GT/s, x1. This is the internal host-side connection used by the controller; it should not be confused with the 2.5 Gb/s Ethernet link exposed to the network.

On an integrated motherboard implementation, the board vendor decides how that controller is connected and exposed. A discrete network adapter can use the same I226 controller while adding its own PCB, RJ-45 connector, bracket and supporting circuitry. The controller specification is therefore not a complete motherboard or add-in-card specification.

Intel marks jumbo-frame support and IEEE 1588 support as present on the I226-V. Jumbo-frame capability means the controller can participate in networks using larger Ethernet frames, but a useful jumbo-frame deployment requires compatible configuration across the relevant endpoints and network path.

IEEE 1588 is the Precision Time Protocol standard used for precise network time synchronization. Intel listing IEEE 1588 support is a controller capability; it does not establish that a particular Windows application, Linux configuration, switch or motherboard automatically exposes every timestamping workflow without additional software and configuration.

Intel’s current operating-system support matrix lists I226-V support for Windows 11 and identifies e2fn as the Windows 11 driver family. The same matrix lists Windows 10 client support for I226-V, while its Windows Server columns are not marked supported for the V variant.

Intel also states that Intel PROSet for Windows Device Manager and Intel Advanced Network Services driver features for teaming and VLANs are not supported by I225/I226. That boundary matters when older Intel Ethernet setup guides or enterprise NIC instructions refer to those software features: controller support for Ethernet itself does not imply support for every legacy Intel management feature.

Intel’s support matrix identifies igc as the Linux driver for its 2.5GbE I225/I226 controllers and lists I226-V support in current Linux-family rows. Intel specifically notes that the standalone or out-of-tree igc driver is unsupported and directs users to the driver corresponding to the operating-system kernel.

For a real Linux system, distribution kernel age and vendor support still matter. The controller being supported by igc does not mean every old kernel or installer image necessarily contains a sufficiently recent implementation for I226-V.

Intel lists three I226 controller variants: I226-V, I226-LM and I226-IT. All are single-port 2.5G controllers using a PCIe 3.1 system interface, but their product roles and feature sets differ. Intel marks embedded options unavailable for I226-V while the LM and IT variants are listed with embedded options.

Intel’s family material also discusses vPro and Active Management Technology in the context of enabled systems. Those platform-management capabilities should not be inferred from the I226-V name alone. A complete vPro or manageability claim depends on the specific controller variant and the rest of the supported platform.

To establish a 2.5 Gb/s Ethernet link, the PC controller and the device at the other end of the cable must negotiate a compatible rate. Intel’s I226 family supports fallback Ethernet rates as well as 2.5GbE, so seeing a 1 Gb/s or 100 Mb/s negotiated link does not by itself mean the controller is defective.

Check the exact motherboard or adapter documentation for the physical port implementation, then check the switch or router port and cabling when diagnosing a lower-than-expected negotiated rate. Treat measured transfer performance as a separate question from the controller’s documented link capability.