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Intel

Intel E10G42BTDAG1P5 X520-DA2 10Gigabit Ethernet Card

★★★★★2.2 (2 reviews)

Dual 10GbE SFP+ ports on a single PCIe card eliminate the bandwidth ceiling that 1GbE imposes on NAS, VM, and high-throughput storage workloads.

$58.99*
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*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.

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Overview

The Intel X520-DA2 is a dual-port 10 Gigabit Ethernet adapter built on the Intel 82599ES controller, using SFP+ ports that support both Direct Attach Copper cables and optical transceivers. What the specifications mean in practice: two fully independent 10Gbps interfaces on a PCIe 2.0 x8 card, with hardware offload engines for TCP segmentation, large receive, and iSCSI — capabilities that shift the computational burden of high-throughput networking off the host CPU and onto dedicated silicon. In storage-heavy workloads like iSCSI SANs, NFS NAS traffic, or VM live migration, this offload directly translates to lower CPU utilization and more consistent latency.

The X520-DA2 targets server administrators, virtualization architects, and power users who have outgrown 1GbE aggregation. Its SR-IOV support makes it a natural fit for VMware ESXi, KVM, and Hyper-V deployments where individual VMs benefit from direct hardware-level NIC access rather than passing through a software virtual switch. For storage workloads on TrueNAS, Proxmox, or Windows Server, the combination of dual 10GbE ports and mature driver support means the card integrates cleanly without exotic configuration. The main deployment consideration is SFP+ transceiver compatibility — using Intel-validated modules or Intel-qualified DAC cables avoids the driver friction that third-party optics can introduce.

Key Features

E10G42BTDAG1P5

INTEL

Specifications

Brand
Intel
Model
E10G42BTDAG1P5 (X520-DA2)
Controller
Intel 82599ES
Port Type
SFP+ (Dual Port)
Port Speed
10 Gigabit Ethernet per port
Interface
PCIe 2.0 x8
Virtualization
SR-IOV supported
Offload Support
TSO, LRO, iSCSI offload

Pros & Cons

👍 Pros

  • Dual independent 10Gbps ports on a single card doubles throughput capacity compared to a single-port adapter without consuming an additional PCIe slot.
  • SR-IOV support allows virtual function assignment directly to VMs, reducing hypervisor overhead and improving latency in dense virtualization environments.
  • Hardware TCP/iSCSI offload engines reduce CPU utilization during sustained data transfers — measurable in high-throughput NAS and backup workloads.
  • The ixgbe driver in Linux is mature and stable, with consistent performance across kernel versions without requiring proprietary driver packages.
  • PCIe 2.0 x8 interface provides headroom for both ports to operate at line rate simultaneously without bus saturation.

👎 Cons

  • Intel's driver enforces SFP+ transceiver validation — third-party optical modules may trigger compatibility warnings that require manual overrides, adding deployment friction in mixed-vendor environments.
  • The card runs warm under sustained dual-port load and lacks active cooling; adequate case airflow is required in dense server configurations to prevent thermal throttling.
  • No 25GbE or higher upgrade path — organizations planning a near-term move to 25GbE infrastructure will need new hardware rather than a firmware update.
  • Driver support on Windows Server requires attention to version matching — older or newer OS versions may require manual driver installation rather than plug-and-play enumeration.

Frequently Asked Questions

The X520-DA2 uses a PCIe 2.0 x8 interface. It is backward and forward compatible with PCIe 3.0 and PCIe 4.0 slots — running it in a PCIe 3.0 x8 slot gives you more than sufficient bandwidth headroom for both 10GbE ports operating simultaneously.
The X520-DA2 supports Intel-qualified SFP+ Direct Attach Copper (DAC) cables for short runs and standard SFP+ optical transceivers (SR, LR) for fiber connections. Note that Intel's driver has historically been strict about transceiver validation — third-party SFP+ modules may require a registry or driver tweak to suppress compatibility warnings, particularly on Windows Server.
Yes — the X520-DA2 supports SR-IOV (Single Root I/O Virtualization), which allows a single physical port to be partitioned into multiple virtual functions assignable to VMs. It is on VMware's HCL for ESXi and has mature driver support in Linux (ixgbe driver) and Windows Server 2012 R2 through 2022.
Each port operates independently at up to 10Gbps — the PCIe x8 interface provides approximately 32Gbps of aggregate bandwidth (PCIe 2.0), sufficient for both ports to saturate simultaneously without the interface becoming the bottleneck.
The X520-DA2 supports TCP Segmentation Offload (TSO), Large Receive Offload (LRO), and iSCSI offload, which meaningfully reduce CPU overhead during sustained storage traffic. For NAS or SAN workloads over 10GbE, these offloads are the reason enterprise environments prefer dedicated NICs over software-only solutions.

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