Network Interface Card (NIC) Basics: What to Consider – TechMikeNY


Network Interface Card (NIC) Basics: What to Consider


Continuing our series on Server Anatomy 101, we’re going to go over the basics of Network Interface Cards (NICs)! These bad boys are the vital components responsible for connecting your server to a network. When you’re building your own server, understanding the basics of NICs is the key to ensuring your server is able to handle the demands of your network. In this blog post, we’ll go over how to choose the perfect NIC for your server build.

NDC’s vs NIC’s

A Network Interface Card (NIC) is a hardware component that provides a connection between a computer/server and a network, and then manages communication across that connection. The primary difference between NICs and Network Daughter Cards (NDCs) is that NDCs are usually specific to certain server or computer models, whereas NICs are standalone PCI cards that can be added to a system to provide network connectivity.


Dell network daughter card and HP network daughter card


When selecting your NIC, you’ll want to make sure that it aligns with the type of cable interface you’ll be using to connect your server to the network. 

The most common type of connectivity for NICs is Ethernet. These are usually connected through Cat5e, Cat6, and Cat6a cables. Cat5e cables typically support speeds up to 1Gbps, and are widely used to connect NICs in both home and business networks; Cat6 cables are capable of speeds up to 10Gbps, and are generally meant for supporting higher-performance networks (such as data centers).** Cat 6a cables have even higher speeds, with a maximum of 10Gbps as well, but with longer supported distances than Cat6. Other non-ethernet connectivity options for high-speed and low-latency networks include fiber optic connectors and Infiniband. 

NICs have different kinds of ports for different connectivity. For example, if your network uses Cat5e, Cat6, or Cat6a cable, you’ll need to select a NIC with an RJ45 jack that is compatible with an 8P8C modular connector. (You’ll also need to check that the connector you’re using is designed for the cable you’re using; for example, some RJ45 connectors are designed for use with stranded cable, while others are meant for use with solid core cable.)


rj-45 vs sfp

If your network uses fiber optic cables, a NIC with a Small Form-factor Pluggable (SFP) or QSFP connector will generally fit the bill. Fiber optic cables support all connections above 10GBs ( 25GB/40GB/100GBs). If you’re connecting to an Infiniband network, use an Infiniband connector (which typically uses the SDR, DDR, and QDR connectors). Using a faster NIC may result in slightly more significant power usage, so be sure to keep your power supply in mind.

Infiniband Port

Note: SFP ports can have modules that allow you to use copper cables (such as Cat5e, etc.), but RJ45 ports are not compatible with SFP ports (or fiber optic cables).

SFP Module for Fiber Optic Cables



This may seem intuitive, but for optimal performance, the NIC you’re using should match the speed of your network. If you’re building a server that needs to support higher speeds but are stuck with a NIC that can’t handle it, you might end up with lower overall performance and potential data loss, as a NIC not meant to handle high-speed data transmission could drop or corrupt packets. To ensure that you won’t have to replace your NIC later as your network evolves, consider its potential growth; think bandwidth requirements of your applications, the number of users accessing your network, and the overall network traffic.

Network traffic management

Another factor to pay attention to is your NIC’s Quality of Service Capabilities (known as QoS). QoS is a network management technique that helps prioritize network traffic to ensure that more important data is transmitted faster and more reliably than other data. It’s kind of like a real-time triage. In other words, QoS ensures that your network resources are utilized in a way that provides a consistent level of service for different types of network traffic. 

Some NICs come with built-in QoS capabilities, while others rely on routers or network switches. A NIC with built in QoS functionality gives you more control; having better visibility into how your network traffic is being managed allows you to make more informed decisions. These are also more cost effective than purchasing a separate network switch with QoS capabilities, especially for smaller networks. However, if you’re looking for more centralization of, say, a larger network, you may be okay with relying on a network switch.

Number of ports


A NIC can either have 1, 2, or 4 ports. Having multiple ports, as in the case of 2-port and 4-port NICs, provides you with the option to connect your server to multiple networks or to bond two ports together (to provide increased bandwidth). If you want a higher level of network connectivity and redundancy, you’ll want to use a NIC with more ports.

2 sfp 4 rj-45

Compatibility with server/server OS

Last, but definitely not least: compatibility. In order for your NIC to work as intended (or work at all), it needs to be compatible with both your server and the operating system that is installed on your server. Some NICs may require additional software or drivers to function properly. If the NIC is incompatible, you may run into connectivity issues, slow speeds, or issues pertaining to the server’s communication with other devices, so make sure you research compatibility before purchasing. In general, older NICs will work on newer servers, but may not work with newer OS versions; older servers may or may not accept newer NICs.


Final thoughts


Network interface cards are a critical component for the smooth functioning of your entire network infrastructure. For the best results, it's important to  research your system requirements and carefully consider your speed and quality-of-service needs when choosing the right NIC for your network.

Unsure of what kind of NIC you might need? Contact us at, and one of our techs will happily walk you through it. That’s what we’re here for!


  • Thanks for the question, Dean. It’s important for NIC’s to support more than just the fastest speed to ensure compatibility with older connections and cabling; network environments are diverse, and different devices or network segments may have varying speed capabilities or requirements.

    As for choosing the right NIC, your best bet is really just thoroughly researching your system’s requirements. The connection should match with your existing network hardware; however, the components on the servers are easily upgradeable, so remember, you’re not stuck with one type of connection forever. You can add a PCI NIC with a different type and speed of connection and you can change your network switch to match the new connections, be it 10GB Copper/RJ-45 Connections or 10/25/40GB Fiber SFP connections.

  • Why is it important for NICs to support more than just the fastest speed, and how do you choose between which NIC you might need?

    Dean Moore
  • Hey Mike,

    Great question, thanks for asking! Dell doesn’t have a central directory with that information, but we compiled a table together for Dell’s NDC’s compatible with 12th and 13th/14th gen servers.

    Here’s the link to copy and paste if you’d like to check it out:

  • One thing that is daunting is the expansive list of NICs& NDCs have boards that look equivalent (eg 4×1G RJ45) but have very different prices and only Dell bingo numbers to distinguish them. given the evolution of the Ethernet chips, knowing which part is on the card is golden. Is there an xref somewhere for the Dell novitiates?

    Mike O'Dell
  • Hey Zach,

    Good catch! Just fixed it, thank you for letting us know.


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