PCIE X8 to 2x 10GbE SFP+ Fiber Adapter - HighSpeed Server NIC

In this review the FebSmart X520-DA2 is evaluated as a compact, performance-focused network adapter for users who need reliable 10GbE links. The bottom line: this PCI Express X8 card delivers two independent 10GbE SFP+ ports driven by the Intel 82599ES controller, making it a practical choice for Windows and Linux desktops, servers, NAS, and virtualization hosts that require low-latency, high-throughput networking. For anyone upgrading from 1GbE or adding SAN connectivity, the X520-DA2 provides the core features needed for 10GbE deployments, provided you supply compatible SFP+ modules or DACs.

Key Features

• Intel 82599ES controller: Provides proven 10GbE performance and broad driver support across Windows Server and many Linux distributions for stable throughput.
• Dual SFP+ ports: Two 10GbE SFP+ fiber ports let users choose 10GBASE-SR, 10GBASE-LR transceivers or SFP+ copper direct attach cables for flexible physical media.
• PCIe X8 interface: Uses a PCIE 2.0 X8 lane with up to 40Gbps total bandwidth so both ports can operate at full 10Gbps when installed in an active X8 or X16 slot.
• Virtualization and storage features: Supports VT-c, VMDq and SR-IOV plus iSCSI and NFS offloads, which reduce CPU overhead in virtualized and storage environments.
• Standards and management: Implements IEEE 1588 and other Ethernet standards plus on-chip QoS and traffic management for deterministic network behavior.
• OS compatibility: Driver-free on recent Windows Server releases and supported on many Linux distros, FreeBSD and VMWare ESXi when using the appropriate ixgbe drivers.

Who It's For

The X520-DA2 is aimed at IT professionals and advanced hobbyists who need dual 10GbE connectivity without a large, full-height adapter. It fits well in small servers, workstations, and NAS systems where adding SFP+ fiber or DAC links improves throughput for backups, virtualization, or storage traffic.

It is not ideal for casual users who expect plug-and-play copper RJ45 10G out of the box, since SFP+ transceivers or DAC cables must be purchased separately and some desktop Windows versions require manual driver installation. Users needing integrated RJ45 10G or integrated switch ports should look elsewhere.

Pros & Cons

Pros

• Dual 10GbE SFP+ ports with Intel 82599ES deliver dependable high-speed connectivity.
• Good OS support for enterprise servers and popular Linux distributions when using provided drivers.
• Virtualization and storage offloads help lower CPU load in demanding environments.
• Includes low-profile and full-height brackets for flexible installation in varied chassis.

Cons

• Requires separate purchase of SFP+ modules or DAC cables, which adds cost and complexity.
• Needs an active PCIE X8 or X16 lane to achieve full dual-port 10Gbps performance, so older systems may not deliver full speed.

Specifications

Controller	Intel 82599ES 2x 10GbE
Network ports	2x 10GbE SFP+ fiber ports
Supported media	10GBASE-SR, 10GBASE-LR transceivers, SFP+ DAC
Host interface	PCIe 2.0 X8 (works in X8 or X16 slot)
Bandwidth	40Gbps total PCIe lane bandwidth
OS support	Windows 7/8/10/11 (drivers), Windows Server driver-free, Linux (ixgbe), FreeBSD, VMware ESXi

Our Verdict

The FebSmart X520-DA2 is a practical, value-focused dual 10GbE SFP+ adapter for users who need reliable high-speed LAN or SAN connectivity and are comfortable selecting SFP+ transceivers or DACs separately. Its Intel 82599ES silicon, virtualization features and broad server-class OS support make it a smart upgrade for workstations, NAS and virtualization hosts, though installers should confirm an active PCIE X8/X16 lane to ensure full dual-port performance.

Frequently Asked Questions

Do I get cables or transceivers with the card?
No. The adapter requires separate 10GBASE-SR, 10GBASE-LR transceivers or SFP+ copper DAC cables, which must be purchased separately.

Will it work in any PCIe slot?
It fits in X8 or X16 slots but needs an active PCIE X8 or X16 lane to achieve full dual 10Gbps performance; passive or limited lanes may restrict speed.

Which operating systems are supported?
Driver-free on modern Windows Server editions and supported on Windows desktop OS with drivers; Linux requires the ixgbe driver and many popular distributions are supported.