External hard drives: Which one is right for you?

By Nadine Hantke Sep 12, 2010, 14:24 GMT

Hamburg - It's a familiar problem for many computer users: the hard drive is full. Gigabyte after gigabyte of music, images and videos add up.

The solution, however, is clear: an external hard drive, even if it's only for data backups. After all, nobody wants to be the one who loses his entire music collection or vacation photos in one fell swoop.

A visit to the electronics store can be confusing, though, with dozens of devices on the shelves. How can you choose the right one?

First, a rule of thumb: the bigger the hard drive capacity, the cheaper each unit of storage space. A recent study by Germany's Computer Bild magazine found that for a 500 gigabyte hard drive, each gigabyte costs 16 cents; for a 1,500 or 2,000 gigabyte hard drive, that same gigabyte costs only 8 cents.

Normal users will have a hard time filling up hard drives with a terabyte (1000 gigabytes) of memory. After all, a terabyte can hold around 250,000 photos, 400,000 songs or 385 hours of standard video, the German consumer testing organisation Stiftung Warentest notes.

The most popular types of drive at the moment are 2.5-inch hard drives with 500 gigabytes of storage capacity and 3.5-inch drives with 1,000 gigabytes. Choosing between them is a matter of priorities.

'You should generally consider whether you want to have the freedom of mobility or whether you want cheap storage,' says Michael Schmidt, the technology editor at Computer Bild.

The 2.5-inch drives are significantly smaller and more robust, making them better suited for transport than their bigger 3.5-inch brothers.

'The large hard drives are better suited for large volumes of data, but should remain protected at home,' says Falk Murko from Stiftung Warentest.

The test magazine recently found that most of the smaller drives survived a drop test, while the 3.5-inch drives didn't.

An additional mobility benefit for the 2.5-inch hard drives is that they can typically draw their energy via USB cable. The larger external hard drives require a power supply.

'If you want to transport data with the external devices, then the 2.5-inch units make sense. If you want to back up data on your home computer, then the 3.5-inch hard drives are an option, too,' Murko says.

Thomas Littschwager from Chip magazine recommends picking the size of the external hard drive based on the capacity of your computer's internal hard drive.

'The best idea is to take something twice the size of your internal hard drive if you want to use the external hard drive for backups,' Murko says.

Whether 500 gigabytes or a terabyte, both models can be found for as little as 75 dollars. In a comparative test by Stiftung Warentest, almost all of the 2.5 and 3.5-inch hard drives earned a 'good' mark.

'The price differences are bigger than the quality differences,' Murko says.

Schmidt agrees.

'If you buy an external hard drive from a brand-name producer, you generally won't have any big nasty surprises,' he says.

Stiftung Warentest's winner by a nose among the 2.5-hard drives with 500 gigabytes of storage was the Freedom Tough Drive, a relatively expensive device at around 100 dollars.

Computer Bild named the Hitachi Portable Drive (starting at 70 dollars) as the winner in the 2.5-inch category, and the Samsung Story Station (from 79 dollars) as best in class among 3.5-inch models.

The interfaces are one key factor when buying external hard drives. USB 2.0 is standard and must be on hand to ensure that the hard drive can connect to almost any laptop or computer. Data transfer can be quite slow, however.

An external SATA (eSATA) port is faster, as is USB 3.0. The future of data transfer is USB 3.0, Schmidt says.

Littschwager says that 'USB 2.0 speed no longer corresponds to the volume of data being moved around nowadays.' The experts are counting on computers and external hard drives appearing on the market bearing USB 3.0 ports within the next year.

Photos, music and videos cannot generally be watched on a television directly from an external hard drive or listened to via the stereo. However, a multimedia hard drive makes it possible through audio and video outputs that allow consumer devices to be plugged in directly.

This type of hard drive starts from 200 dollars, depending on the size. They are not suitable for backup purposes, however.

As an alternative, a USB multimedia adapter can be hooked up between a 'normal' external hard drive and the television. It reads data from the external hard drive and forwards it on to the stereo or television screen. The adapters have no memory of their own.