Ethernet cards and hubs are available in different speeds. The most common are 10BaseT (10 megabits/second, or Mbps) and 100BaseT (100 Mbps, sometimes cleverly called Fast Ethernet).

Note, however, that the speed of the network has no effect on your computers' Internet speedWeb surfing, email downloading, and so on. The reason: even the slowest network operates far faster than your Internet connection. Remember, the top speed of a cable modem or DSL connection is between 512 and 4,096 kilobits/second (Kbps)still 10 to 20 times slower than the slowest home network (10BaseT network). Even a T-1 line, a permanent leased telephone line commonly used for corporate Internet connections, costing thousands of dollars a month, runs at only 1,544 Kbps.

So why does a faster network matter? Primarily to save time when you're transferring big files between the PCs on the network. For example, you can play MP3 music files stored on another computer over a 10BaseT connection with no problems at all. However, if you plan to install video cameras all around your palatial estate and want to watch all of the video feeds simultaneously, opt for Fast Ethernetor even Gigabit Ethernet, the current Ethernet speed champ (1,000 Mbps).

Much of the Ethernet equipment on the market today is designed to run either at Fast Ethernet speed, or at both 10 and 100 Mbps. If you buy a dual-speed router or hub (often labeled "10/100"), each PC connected to it will run at its own maximum speed. If one computer has a 10BaseT network card and one has 100BaseT, they'll still be able to communicate. But if your hub operates only at 100BaseT speed, then 10BaseT cards won't work at all.

The bottom line? As you shop for gear, buy Fast Ethernet (or 10/100) hubs, which aren't much more expensive than the slower, 10 Mbps hubs. You may as well go for the higher speed, so you'll be ready for any high-bandwidth application that comes down the pike.