The ceiling has just been raised at the top end of the Mac line in terms of raw processing power. Although we knew the 8-core Mac Pro was imminent, in true Apple fashion its launch was anything but predictable. Fireworks and a press conference? Hardly - the upgrade just quietly appeared on Apple's online store.

Unlike the few other 8-core workstations already on the market, the new Mac Pro configuration is the cheapest and only one currently available with twin 3.0GHz quad-core chips. Other machines that can be bought with 8-cores, such as Dell's Precision 690, only work with the option of twin 2.66GHz quad-cores.

If you go to Dell's website and configure an equally matched machine (Dell Precision 690 with twin 2.66GHz quad-core processors, 4GB RAM, equivalent graphics card, hard drive and extras), then the Mac Pro comes in £1,150 cheaper.

This is based on the Mac Pro's basic configuration with 4GB RAM at £449 instead of 1GB, bringing it to a total of £3,108. This lower price is still beyond the means of most of us, but certainly puts paid to the myth that Macs carry some kind of mysterious design premium in their pricing.

Aside from the power bump, the only other change is an expansion of the hard drive capacity. The new configuration will allow for four 750GB SATA drives, giving you a possible total of 3TB onboard capacity, up from 2TB.

Replacing these drives, as with replacing other components inside the Mac Pro tower, is all very easy. The same goes for slotting in more RAM sticks. The more time we spent with our head inside the Mac Pro chassis, the more in awe of it we become.

It's a beautiful piece of engineering, all easy to access and tinker with thanks to such joys as tool-less installation of PCI graphics cards and screw-less hard drive sleds. Anyone could change around the components.

Same again

The tower is the same design as before and contains the same impressive basic specification. Twin optical drive bays share the same SATA bus, although there are two unused SATA couplings for the bays, too, presumably for HD DVD and Blue-ray drives, which, as yet, do not come as an option with the Mac Pro.

As standard, the Mac Pro comes with one 16x double-layer SuperDrive in one of the optical bays. Port options include two FireWire 800 ports, two FireWire 400 ports and five USB 2.0 ports in addition to the usual Mac wireless options and dual gigabit Ethernet.

Feeding the processors, there are eight RAM slots, which will house up to 16GB. One gig of RAM comes as standard but you will need 4GB to get things flying, especially for RAM intensive apps, such as Photoshop.

Because of the type of RAM the Mac Pro uses, latency issues and the different RAM modes, it's better to install eight slots with 512MB, rather than have two slots with two 2GB sticks. Spreading the load in tandem with the number of cores makes the system work far better.

So what kind of power does the 8-core Mac Pro offer over the quad-core? In some cases no advantage, in some cases a third more power and in a few rare instances a massive boost.

We ran two benchmarking apps; Geekbench, which showed a 53% increase in overall performance side-by-side against a 3GHz quad-core Mac Pro, and Maxon's Cinebench 9.5, which gives a more detailed look at the computer's 2D and 3D graphics rendering ability.

The Cinebench told us that, with the 8-core fully powered, it was 47% faster than the last 3GHz quad-core we tested. One obvious result from these figures, which we knew before testing, is that having eight cores does not mean this new Mac has twice the processing power of the previous quad-core Mac Pro.

To explain this there are other factors to consider, such as OS X 10.4's ability to divvy up the command threads between all the processors, the constraints of Intel's antiquated bus system, the amount and position of RAM and drives, graphics cards and, of course, the biggie - whether the software you use works with multithreaded commands.

The vast majority of current software was written for single cores and so isn't optimised for multicore computing. The OS does its best to divide the commands equally, but this adds a layer of buffering that native multithread software avoids. Professional graphics workers should be aware of this and will already be familiar with plug-ins to multithread their software packages.

Adobe After Effects CS3, still in beta, has a preferences option that can be ticked to optimise multithreading, thanks to plug-in support. Running in this mode produced an additional 40% gain over a quad-core Mac Pro.

AutoCAD is multithreaded, and some 3D design apps such as 3ds Max are multithreaded too, and similar gains are to be had with these apps on an 8-core machine. It is only this kind of software that can fully rip into the new core structure.

Straight to the core

Aside from these high-end rendering apps the only way to access the full processing power of 8-cores is to have several apps running in tandem. With so many cores on offer, the OS can channel different apps to different cores.

We ran batches of set jobs in multiple Logic and Final Cut Pro 6 windows, while encoding in iTunes, playing back in iDVD and importing in iMovie, and while mail and ftp clients ran in the background. In this kind of multitasking test the 8-cores trumped the quad core by another 37%.

If you own an older Mac and primarily work with high-end 3D graphics and video software that has optimised threading built in, or if you work with several apps number crunching at the same time, then the 8-core configuration will shave a couple of hours off your day, even if you use a quad-core Mac Pro. If you're upgrading from a G5 or iMac, you'll be blown away.

Is now the time to buy? When Leopard comes out later this year, with its hyped 64-bit abilities and improved capacity to thread commands to multiple cores, then this already blazing computer will get another shot in the arm.

And there's always the chance that Intel will improve the bus architecture that transports data to and from the cores on desktops, like it has done with Santa Rosa technology for mobile chips.

But speculation aside, if you can afford it buy it. We doubt anyone will be disappointed.