Apple Computer this week announced a modest speed bump to its line of PowerBook G4 laptops, increasing the high-end processor from 1.5GHz to 1.67GHz.

That's not all: the refreshed laptop line has gained 512MB of standard RAM, faster graphics, faster hard drives and 8x "SuperDrives," as well as standard 802.11g-based wireless networking, Bluetooth 2.0, and two patent-pending technologies – the scrolling TrackPad and the Sudden Motion Sensor.

"The new TrackPad looks just like the old one, but it works differently," says David Moody, Apple's vice president of worldwide Mac product marketing. "If you touch two fingers to the pad when you reach the edge of the window, it will scroll horizontally or pan vertically within the window."

For users who find the new scrolling feature unnecessary or unwieldy, Apple has added a new Keyboard and Mouse System Preferences option to deactivate it. And this isn't just a software change, according to Moody – it's a physical difference in how the TrackPad works.

Sudden Motion Sensor technology is designed to help protect the PowerBook's internal hard drive. "Our system senses if the PowerBook has been dropped and parks the disk drive's heads and locks them before the PowerBook hits the floor," says David Russell, Apple's senior director of portables and wireless.

"This system is unique to the PowerBook itself – it's built in to the motherboard." As a result, Apple isn't dependent on any specific hard drive manufacturer, Russell says.

What's more, all 15- and 17-inch PowerBooks feature backlit keyboards that are now up to 10 times brighter than previous models and are now available with 1.67GHz G4 processors paired with ATI Mobility Radeon 9700 graphics processors with either 64MB or 128MB of dedicated graphics memory. All models now ship from the factory with 512MB of 333-MHz DDR SDRAM and 5400rpm (revolutions per minute) hard drives.

SuperDrive-equipped systems now ship with 8x DVD+/-RW/CD-RW optical drives, in place of the 4x drives previously used.

All PowerBooks now ship with AirPort Extreme networking built-in, enabling them to work with IEEE 802.11g-compliant 54 mbps wireless networking. Apple also claims to be the first notebook maker to integrate Bluetooth 2.0 on its computers.

The PowerBook range starts at £1,049.