40G Network Card Buying Guide: Intel XL710-T2 QSFP+ Adapter Explained
What Is a 40G Network Card and Who Needs One?
A 40 Gigabit Ethernet (40GbE) network card delivers up to 40Gbps of bandwidth per port — 40 times faster than standard Gigabit Ethernet. If you're running a data center, a high-density NAS, a virtualization cluster, or a high-performance computing (HPC) environment, a 40G NIC is no longer a luxury — it's a necessity.
Common use cases include:
- Storage area networks (SAN) and NAS with multiple simultaneous users
- VMware, Hyper-V, or KVM virtualization hosts requiring SR-IOV
- Scientific computing and financial modeling clusters
- Backbone uplinks between top-of-rack switches
Why the Intel XL710-T2 Is the Industry Standard
The Intel XL710-T2 controller is widely regarded as the gold standard for enterprise 40GbE networking. Here's why IT professionals consistently choose it:
- Proven reliability: Intel's XL710 chipset powers deployments in Fortune 500 data centers worldwide.
- SR-IOV support: Single Root I/O Virtualization allows multiple VMs to directly access the NIC, dramatically reducing hypervisor overhead.
- Advanced network virtualization: Native support for VXLAN, NVGRE, MACinUDP, and IPinGRE — essential for modern SDN and cloud infrastructure.
- Broad OS compatibility: Works out of the box with Windows Server 2008–2016, Windows 7/8/10, Linux Kernel 2.4.x through 4.x+, and VMware 6.x.
- Low power consumption: Approximately 15–20W under full load, with no additional power connectors required.
Key Specifications at a Glance
| Specification | Details |
|---|---|
| Controller | Intel XL710-T2 |
| Ports | 2x QSFP+ (40Gbps per port) |
| Host Interface | PCIe x8 / x16 (Gen 3) |
| Network Standard | 40GBASE-SR4, 40GBASE-LR4, QSFP+ AOC/DAC |
| Jumbo Frames | Up to 9.5 KB |
| Virtualization | SR-IOV, VXLAN, NVGRE, IPinGRE |
| OS Support | Windows, Linux, VMware |
| Power | ~15–20W, no aux connector needed |
| Form Factor | Standard + Low-Profile bracket included |
QSFP+ vs SFP+: Which Interface Should You Choose?
QSFP+ (Quad Small Form-factor Pluggable Plus) is the standard interface for 40G networking. Unlike SFP+ which handles 10G per lane, QSFP+ bonds four 10G lanes into a single 40G connection. This makes it ideal for:
- Short-range connections (SR4): Up to 100m over OM3 multimode fiber, or 150m over OM4.
- Long-range connections (LR4): Up to 10km over single-mode fiber.
- Direct Attach Cables (DAC): Cost-effective copper connections up to 5m for top-of-rack deployments.
- Active Optical Cables (AOC): Lightweight fiber cables for distances up to 100m.
Can Both Ports Run Simultaneously?
Yes. The Lekuo XL710-T2 dual-port adapter supports full simultaneous operation on both QSFP+ ports, delivering up to 80Gbps aggregate bandwidth. You can configure the ports for:
- Link Aggregation (LACP/802.3ad): Bond both ports for a single 80G logical connection.
- Separate networks: Connect to two different switches or VLANs independently.
- Redundancy (failover): Use one port as active and one as standby for high availability.
PCIe Slot Compatibility: x8 vs x16
This adapter uses a PCIe x8 electrical interface but is physically compatible with both x8 and x16 slots. When installed in an x16 slot, it operates at x8 speeds — which is more than sufficient for 40GbE traffic. It will not fit in x1 or x4 slots.
Installation: What's in the Box?
- 1x Lekuo 40G Dual-Port QSFP+ Network Card (Intel XL710-T2)
- 1x Low-Profile Bracket (for 1U/2U rack servers)
Driver download is available for Windows and Linux. VMware drivers are included in vSphere 6.x and later.
Frequently Asked Questions
Q: Does this card work in a consumer desktop motherboard?
A: Yes, as long as your motherboard has a PCIe x8 or x16 slot. Most modern ATX and EATX boards qualify. Check your BIOS for PCIe Gen 3 support for best performance.
Q: Do I need a special switch for 40G?
A: Yes, you need a 40GbE-capable switch or another 40G NIC on the other end. Popular options include Mellanox/NVIDIA SN2000 series, Cisco Nexus, and Arista 7050 switches.
Q: Is this card compatible with Windows 11?
A: Intel's XL710 driver supports Windows 10 and Windows Server 2016. Windows 11 compatibility depends on the driver version — download the latest Intel driver for best results.
Q: What's the difference between SR4 and LR4 modules?
A: SR4 (Short Range) uses multimode fiber up to 100–150m. LR4 (Long Range) uses single-mode fiber up to 10km. Choose based on your cable infrastructure and distance requirements.
Bottom Line: Is the Intel XL710-T2 Right for You?
If you need reliable, enterprise-grade 40GbE connectivity with full virtualization support, the Intel XL710-T2 dual-port QSFP+ adapter is one of the best choices available. It combines proven chipset reliability, broad OS support, and advanced features like SR-IOV and VXLAN — all at a competitive price point.
Whether you're building a storage server, expanding a VMware cluster, or upgrading your data center backbone, the Lekuo XL710-T2 adapter delivers the performance and compatibility you need.