All External Hard Drives are Not Created Equal
“I’m buying an external hard drive for my backups, as you have often recommended. But I’ve bogged down in the details – capacity, transfer speed, USB vs. Firewire, etc. Can you give me some tips on choosing an external drive for backups?”
Buying an External Hard Drive
External hard drives make it plug-and-play easy to add storage capacity to an existing PC or laptop. An external drive is also handy for storing backup copies of data, especially if you want to back up multiple computers around the home or office. Here are some tips for buying an external hard drive.
There are two broad categories of external hard drive. Desktop drives with 3.5 inch mechanisms inside are designed to stay in one place, usually on your desktop. They generally require a power adapter. Portable hard drives are based on 2.5 inch or 1.8 inch mechanisms, making them small enough to fit in a shirt pocket. Portable drives typically get their power from the computers to which they attach.
Desktop drives currently come in capacities up to 3 Terabytes. If you need even more storage space, look for models that stuff two or more drives into one chassis. Portable drives max out at 1 TB, but capacities of 250 MB to 750 MB are more common and less expensive.
Which Interface: USB, Firewire or eSATA?
One thing that many shoppers find confusing is how best to connect the drive to their computer. External hard drives may have more than one type of interface. USB 2.0 is the most common interface, supporting data transfer speeds of up to 480 Mbps. Firewire 400 and 800 are also common; they transfer data at 400 or 800 Mbps, respectively. An eSATA interface can move data at up to 3 Gbps (3,000 Mbps), making it a favorite if your computer(s) support eSATA. Unfortunately, eSATA does not supply power over its cable (as USB does), so an eSATA external drive will need a separate power cable. USB 3.0 is even faster than eSATA, at up to 5 Gbps. Intel’s Thunderbolt interface is rare (except in Apple computers) but it will hit 10 Gbps.
If speed is a crucial factor for you, check your computer’s manual (or inspect the ports if you’re familiar with them) and purchase a drive with the fastest connection that your computer will support. If speed isn’t of the essence, you’ll probably find a good deal on a drive that connects with a USB 2.0 or Firewire cable. Just be aware that some el-cheapo drives do not come with the required cable.
External Solid-State Drives (SSDs) are available, but they are very expensive on a per-gigabyte basis compared to traditional spinning magnetic drive mechanisms. A simple USB 2.0 500 GB spinning drive may sell for $89, while an eSATA external SSD of the same capacity will cost nearly $2,000! For more information on SSDs, see my article Solid State Hard Drives.
The rotation speed of an external hard drive does not make much practical difference, in most cases. Yes, a 7200 rpm drive is faster than a 5400 rpm drive, but you won’t see the difference through a USB 2.0 or Firewire interface. Both transfer data slower than most 5400 rpm drives can. Remember the old adage about the weakest link in the chain? Case in point here.
Excellent external hard drives are made by a number of well-known brand names; you can’t really pick an overall leader. Seagate, Maxtor, Iomega, Western Digital are all top-flight manufacturers, and intense competition in the hard drive industry means you won’t save much by buying a no-name brand.
Warranties are a more important factor to consider. A reliable hard drive, internal or external, should come with a three to five year warranty. Finally, bundled software may be important to you if you don’t already have backup software.
Do you have any tips on buying an external drive, or a specific model to recommend? Post your comment or question below...
This article was posted by Bob Rankin on 11 Aug 2011
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Article information: AskBobRankin -- All External Hard Drives are Not Created Equal (Posted: 11 Aug 2011)
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