Apple today broke the Gigahertz barrier, announcing its long-expected new configuration G4 Power Macs - with a dual-processor 1GHz PowerPC G4 at the top end.

The top-of-the-range dual-processor machine includes a Nvidia GeForce4 graphics card (64MB of DDR [double data rate] RAM). GeForce4 generates 1.1 billion textured pixels per second, according to Nvidia. The GHz Mac also ships with Apple's DVD/CD burning SuperDrive. It has 2MB of DDR L3 cache per processor as a further boost to performance. The product costs £2,199 (ex VAT). The new Macs support up to 1.5GB of RAM.

The dual 1GHz G4 offers 256K on-chip level 2 cache and comes with 512MB of RAM pre-installed. It hosts an 80GB hard drive.

G4orce Phil Schiller, Apple's senior vice president of worldwide product marketing, said: "The new dual 1GHz Power Mac G4 with Nvidia GeForce4 graphics is the fastest Mac ever, and the fastest personal computer ever for creative professionals. This is the first Mac to break the 1GHz barrier, and the first computer in the world to feature Nvidia GeForce4 graphics."

Apple also introduced 933MHz and 800MHz models.

The £1,699 933MHz 60GB unit hosts an Nvidia GeForce4 MX with 64MB of DDR RAM for graphics. It has 2MB of DDR L3 cache per processor as a further boost to performance. It ships with 256MB of RAM as standard, and offers 256K on-chip level 2 cache, and a SuperDrive.

The 800MHz bottom-of-the range Power Mac costs £1,149. For graphics, this configuration includes ATI's Radeon 7500 with 32MB of DDR RAM. It offers 256K on-chip level 2 cache; 256MB of RAM; a 40GB hard drive and a CD-RW drive.

Display support All configurations feature the G4 Velocity Engine and offer built-in dual monitor support as standard.

Expandability remains the main strength of Apple's top-of-the line Power Macs - each configuration offers four PCI slots, plus the internal AGP slot used by the supplied graphics card. The Macs host three 3.5-inch hard-disk drive expansion bays, with one pre-installed 7,200rpm (revolutions per minute) Ultra ATA hard drive of up to 80GB capacity.

Each Power Mac has two FireWire and four USB 1.1 slots. The Macs have 10/100/1000Base-T Ethernet built-in.

App attack Mac OS X is installed as the default start-up operating system across the range. The new Power Mac G4 ships with a bundle of Mac OS X applications, including: Ambrosia Software's Snapz Pro X; Caffeine Software PixelNhance 1.5; Code Line Communications Art Directors Toolkit for X; Lemke Software GraphicConverter 4.1; Omni Group's OmniGraffle and OmniOutliner; James Thompson Pcalc; FileMaker Pro Trial 5.5; Adobe Acrobat Reader 5.0; Internet Explorer 5.1; Smith Micro FAXstf X Preview; and Apple Developer Tools X.

The units are available in build-to-order configurations through the UK Apple Store. The "ultimate" option includes 1.5GB of RAM and two 80GB hard drives. The machine's other specs are the same as the 1GHz dual-processor Mac.

Apple claims the new Power Macs are available now, UK shipping details remain to be announced.