Network Interface Cards Explained

Network interface cards bring your computer online

NIC is short for network interface card—a type of network adapter hardware that fits in an expansion slot on a computer's motherboard. Most computers have them built-in—in which case, they are part of the circuit board—but you can also add your own NIC to expand the functionality of the system.

A network interface card (NIC).

Dmitry Nosachev / CC BY 4.0 / Wikimedia Commons

The NIC provides the hardware interface between a computer and a network. This is true whether the network is wired or wireless since the NIC can be used for Ethernet networks as well as Wi-Fi.

Network cards that connect over USB are not cards; they are USB devices that enable network connections through the USB port. These are called network adapters.

NIC also stands for Network Information Center. For example, the organization InterNIC is a NIC that provides information to the general public on internet domain names.

What Does a NIC Do?

A network interface card allows a device to network with other devices. They may be used for devices that connect to a central network (like in infrastructure mode), or devices that are paired together, as in ad-hoc mode.

However, a NIC isn't always the only component you need to interface with other devices. For example, if the device is part of a larger network and you want it to have access to the internet, like at home or in a business, a router is required. The device uses the network interface card to connect to the router, which is connected to the internet.

NIC Physical Description

Network cards come in many forms but the two main ones are wired and wireless.

No matter which is used, the NIC protrudes from the back of the computer next to the other plugs, like for the monitor. If the NIC is plugged into a laptop, it's most likely attached to the side.

How Fast Are Network Cards?

All NICs feature a speed rating, such as 11 Mbps, 54 Mbps, or 100 Mbps. These ratings only suggest the general performance of the unit. You can find this information in Windows by right-clicking the network connection from the Network and Sharing Center > Change adapter settings section of Control Panel.

The speed of the NIC does not necessarily determine the speed of the internet connection because of reasons like available bandwidth and the speed you pay for. In other words, the speed of the network, when these two factors are considered, is determined by the slower of the two.

For example, if you pay for 20 Mbps download speeds, using a 100 Mbps NIC will not increase your speeds to 100 Mbps, or even to anything over 20 Mbps. However, if you pay for 20 Mbps but your NIC only supports 11 Mbps, you will suffer slower download speeds since the installed hardware can only work as fast as it's rated to work.

Another major factor in network speed is bandwidth. If you're supposed to get 100 Mbps and your card supports it, but you have three computers on the network that are all downloading simultaneously, that 100 Mbps will be split in three, which will serve each client around 33 Mbps.

How to Get Drivers for Network Cards

All hardware devices need device drivers to work with the software on the computer. If your network card isn't working, it's likely that the driver is missing, corrupted, or outdated.

Updating network card drivers can be tricky since you usually need the internet to download the driver—and it's the driver that's preventing you from accessing the internet. In these cases, download the network driver on a computer that works and then transfer it to the problem system with a flash drive or CD.

The easiest way to do this is to use a driver updater tool that can scan for updates even when the computer is offline. Run the program on the PC that needs the driver and then save the information to a file. Open the file in the same driver updater program on a working computer, download the drivers, and then transfer them to the non-working computer to update the drivers there.

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