It’s ironic that the first workstation PC we’ve ever reviewed sporting dual Intel Core-based processors is in fact an Apple Mac. The new replacement for the G5 Power Mac marks the final nail in the coffin for PowerPC processors in Apple’s product range. Inside is a pair of Intel Xeon 5160 dual-core CPUs running at 3GHz, making the Mac Pro a quad-core machine. The 5000 series is based on Woodcrest cores, using the Core micro-architecture for a processor more or less identical to the Core 2 Duo. The major differences are a 1.33GHz front-side bus speed and the increased 3GHz top-end frequency of the 5160s.

Although not explicitly acknowledged by Apple, the chipset is Intel’s own 5000X series, equipped with an FB-DIMM memory interface. This allows for the hefty complement of eight DIMM sockets, for a maximum of 16GB of 667MHz FB-DIMM RAM. Our review unit came kitted out with four 1GB modules.

The machine looks identical to the old G5, which is no bad thing. On top of its looks, the build quality is something that no other desktop-PC case manufacturer has ever come close to, in our experience.

Once the side panel’s been removed, the internals look very different to a standard PC. Instead of the aluminium outer giving way to a bent-tin skeleton, the sleek look continues beneath the skin. The design is highly modular: aluminium slide-out drive cages are arrayed at the top of the case, slung beneath the power supply and able to accommodate up to four SATA hard disks. No SATA cables are required – you just attach a drive to a tray and slide it into place – but the drives aren’t actually hot-swappable. Our test machine arrived with a 250GB Seagate Barracuda 7200.9 boot drive and three 500GB Hitachi Deskstar drives in software RAID.

The custom Apple-designed motherboard is almost obscured by the ducted cooling system, with the dual processors housed in the forward lower part of the case, using air collected through the front grille and blown over their heatsinks by a 120mm fan. The air continues towards the back, over the RAM and through a rear 120mm exhaust fan. Rather than slotting directly into the motherboard, two sets of four FB-DIMM sockets sit on a pull-out daughtercard each, making for completely unfettered access. The graphics card – an Nvidia Quadro FX 4500 workstation part – is fitted with an extra plate to bring it up to full length, allowing it to be supported by the set of rails fitted to the inside of the chassis. It all adds up to a system that could shame any standard PC.

The Mac Pro comes with Mac OS X pre-installed, but the first thing we did was download the Boot Camp dual-boot installer from Apple’s website and install Windows XP. It’s worth noting that an EFI firmware update from Apple – the equivalent of a PC BIOS update – was needed to get the 5000X SATA driver working properly.

The basic speed of the Mac Pro is what you’d expect from a machine equipped with two 3GHz Core-micro-architecture CPUs: absolutely blistering. Where it’s fully able to make use of all four cores, the Mac Pro blows everything else we’ve seen out of the water. The most impressive score is under the multiple applications test, where it scores 2.60 overall. Barely less impressive is the 3ds Max render; almost a pure CPU horsepower test, bringing in an amazing score of 2.24.

But the performance does come with some qualifications. Under Mac OS X, the system comes configured with software RAID0; there’s no hardware RAID controller on the board. We installed XP using Boot Camp’s default single-drive setup. Consequently, applications that are disk bound, such as Photoshop (or unable to make use of all four cores, such as Office), bring down the overall score, but it still adds up to the fastest PC we’ve ever seen with an overall result of 1.97.

It’s a shame the pure-Windows world can’t come up with anything as well integrated as the Mac Pro. As it is, the drawback of using the machine under XP is that none of the workstation apps you want to run will be ISV-certified under what’s still a beta implementation of XP on a Mac. It’s hard to totally recommend a machine costing almost $12,000 that won’t be running in a “fully supported” mode. But if this isn’t a problem for you, the Mac Pro is one of the fastest, best-designed and best-engineered workstations on the planet.