Network card illustration explaining Ethernet, RJ45 vs SFP, and Wi-Fi standards for PCs, workstations, and servers.

Network Cards Explained

A practical guide to Ethernet, SFP vs RJ45, Wi-Fi standards (including Wi-Fi 7), and how to choose the right networking options for a custom-built PC, workstation, or server.

Basics

What Is a Network Card (NIC)?

A network card—also called a Network Interface Card (NIC)—is the hardware that connects your computer, workstation, or server to a network. That network can be wired (Ethernet) or wireless (Wi-Fi), enabling access to the internet, shared storage, other PCs, and business services.

Wired Networking

What Is Ethernet?

Ethernet is the most common wired networking standard. It is stable, low-latency, and typically faster than Wi-Fi—making it the preferred choice for servers, workstations, virtualization, NAS/file transfers, and AI workloads.

Compatibility reminder: A faster network card won’t help if your switch, router, cabling, or storage can’t support the same speed.

RJ45 Ethernet (Copper)

RJ45 is the standard “Ethernet jack” used with Cat5e/Cat6/Cat6A cables. It’s widely supported and easy to deploy.

1GbE: Standard for most homes and offices
10GbE: Great for NAS/file transfers, virtualization, and shared storage workflows
25GbE: High-performance networking for advanced workstation/server environments

SFP / SFP+ / SFP28 (Fiber or Direct Attach)

SFP ports use removable transceivers. They can run over fiber (longer distance) or DAC cables (short, high-speed copper links).

SFP

Commonly used for 1Gb connections

SFP+

Typically used for 10Gb connections

SFP28

Used for 25Gb connections

Why use SFP?

Flexibility, longer runs, and reduced electrical interference

Caution: SFP networking requires the right transceivers and a compatible switch. Always confirm the exact SFP standard and supported speeds before selecting SFP-based networking.

Wireless Networking

What Is Wi-Fi?

Wi-Fi is wireless networking that connects devices without Ethernet cabling. It is convenient for general use and for systems where wiring isn’t practical, but performance can vary based on distance, walls, interference, and the quality of your router or access point.

Why Some Motherboards Include Wi-Fi

Convenience for home and office desktops
Cleaner installs when Ethernet cabling is difficult
Useful as a backup network path

Why Many Servers Do Not Include Wi-Fi

Ethernet is typically faster, lower latency, and more consistent
Server environments prioritize uptime and predictable performance
Wireless is more susceptible to interference and signal variation
Security policies often restrict wireless networking in server deployments

Wi-Fi Standards (and Why They Matter)

Wi-Fi 5 (802.11ac): Reliable for general use
Wi-Fi 6 (802.11ax): Faster and better in crowded environments
Wi-Fi 6E: Adds 6GHz support for less congestion (requires 6E-capable router/AP)
Wi-Fi 7 (802.11be): Designed for higher throughput, lower latency, and better handling of multiple devices in busy networks (requires Wi-Fi 7 router/AP to see full benefit)

Caution: Wi-Fi speed and stability depend on your router or access point. To get the benefits of Wi-Fi 6/6E/7, make sure your wireless infrastructure supports the same standard (and is positioned well for coverage).

Advanced Use

Why Would You Want Multiple Network Cards?

Multiple network interfaces can improve performance, security, and reliability—especially for servers and advanced workstations.

Traffic separation: keep storage, management, and internet traffic on different networks
Virtualization: dedicate ports for VMs, containers, or lab environments
Link aggregation: combine ports for more bandwidth (requires compatible switch configuration)
Redundancy/failover: maintain connectivity if a cable, port, or switch fails
Dedicated backup network: keep backups from competing with normal work traffic

Tip: If you’re upgrading to 10GbE or 25GbE, confirm your switch ports, cabling, and storage throughput can actually take advantage of the speed increase.