How Many USB Ports Do You Need?

And what to do if you don’t have enough!

Just about every computer peripheral and accessory interfaces with the computer via the USB port. A few short years ago, we had serial ports, parallel ports, SCSI, and even FireWire ports. While many computers and devices still use these connections, they are rapidly becoming niche connections for the most part. The question I want to tackle is the number of USB ports that a computer should have. We’ll also look at expansion options.

I’d like to divide the USB accessories into two types. The first are devices that stay attached to their USB port on a longstanding basis. We’ll call these the resident devices. These peripherals, like printers, are better connected via rear USB ports where the clutter of wires can be more hidden. The second type are devices that are only intermittently plugged into a port. We can designate these migrant devices. These are best joined to the computer through a front mounted USB port for easy access. An example of this is a digital camera to download the pictures, but is away from the computer the rest of the time.

Here’s the list of devices that are resident USB devices:
- Printer
- Scanner (an all-in-one printer/scanner only needs one port)
- WiFi (if not built in)
- External hard drive
- Wireless mouse/keyboard
- Secondary optical drive (especially important for a notebook)
- Flash card reader
- Bluetooth radio (if not built in, and needed)

And here’s the list of the migrant devices:
- Digital camera
- iPod/MP3 player
- USB flash drive
- Webcam (some users keep theirs permanently attached)
- Palm/Pocket PC

The above list represents the mainstream categories of devices that most users have around. Some enthusiasts have even more, but I’m just talking about the mainstream folks. Not to mention all the weird USB items out there like fans, beer coolers, and lights.

I would consider that the computer should have a minimum of 4 rear mounted USB ports, and 2 front mounted USB ports. Power users should reasonably double these numbers to 8 rear, and 4 front. This will insure that there is an available port for peripheral expansion when you need it.

Unfortunately, most computers out there don’t come with that many ports unless they are very new. This leaves a port shortage with four possible solutions:
1. Have less devices (least preferable, only as a last resort).
2. Take advantage of the “hot pluggable” nature of USB (no reboot required) by plugging and unplugging the USB devices as needed. This USB juggling is workable, but rapidly tiresome.
3. Use a USB hub. This allows you to turn one port into several more. Most USB hubs have from 4 to 8 ports. The powered ones are generally better, but more expensive. This is a better option for low bandwidth, nonpowered and intermittently used devices. In other words, a flash card reader will function better on a hub than a USB powered optical drive. The issue is that the USB bandwidth of the one port gets divided among all the ports on the hub.
4. A USB add in card. This is the ideal solution. The drawbacks are that you need a free PCI slot, and the ports will be rear mounted. Oh, and you have to open up your computer for the upgrade (never a limiting factor among the TechNudge diehards). The cards have from 2 to 5 USB ports. Each will be powered, and have full bandwidth. Notebook users can consider an expansion card via the PCMIA slot.

With some planning, and knowledge, most computers can be expanded to accommodate all of your USB devices. Don’t forget to check how many USB ports you’re getting when it comes to your next computer, or motherboard purchase.

Also, on a notebook, take care to see that the USB ports are spaced out far enough to be useable. On many notebooks (like mine), the three ports are so close together, that really only two of them can be used simultaneously with most peripherals. (Note to notebook manufacturers: space the ports a little further out, and put them on both sides of the notebook.)

It’s true what they say “You can never be too rich, too thin, or have too many USB ports!”

--Jonas