Western Digital (WD) has increased the data capacity of its My Book PC and Mac external desktop drives to store up to 4TB (3TB for the Mac version).

The redesigned drives feature USB 3.0 for speedy file transfers and come with WD's SmartWare Pro software that automatically backs up data to Dropbox.

As with WD's My Passport Slim HDDs that were unveiled earlier this month, you'll be able to keep your drive's contents private using the company's own security software that offers data encryption and password protection capability.

If it's the thought of your PC going into meltdown that keeps you awake at night, the drives are also bundled with Acronis True Image that can restore a backed up machine's contents on demand.

Time machine

Though the Mac versions of the drives are slightly more expensive than their PC counterparts, you'll get the added bonus of full compatibility with Apple's Time Machine software that provides one-click backups and automatic backup scheduling.

Both PC and Mac versions of the drives are available now from Western Digital's website. The company has given a Manufacturer's Suggested Retail Price (MSRP) of £79 (US$130) for the 2TB PC model, £99 (US$160) for the 3TB version and £149 (US$240) for the 4TB version.

If you're on a Mac, WD has listed a MSRP of £99 (US$160) for the 2TB model, or £129 (US$208) for the 3TB version.