Power Mac G5 single 1.8GHz

When Apple originally launched the Power Mac G5 range in June 2003, there was a mix of single- and dual-processor systems. The single-chip G5s ran at 1.6GHz and 1.8GHz, with a dual-G5 model topping the range at 2GHz. Later, a two-G5 1.8GHz system was made available – there was such a great demand for the top-end dual that stocks were quickly exhausted. This overwhelming call for multiprocessing Power Macs led Apple to move to a dual-only range shortly after. But now the company has reinstated an entry-level, single-chip model into the Power Mac family.

The most attractive thing about this new entry-level system is its price. At £1,099, it’s £450 cheaper than the original entry-level system (which was slower at 1.6GHz) and a whopping £750 less than the first single-1.8GHz G5 – although that model was then higher in the chain.

We rushed to get our hands on this newly affordable Power Mac G5, and our test results are more interesting than the technical specifications suggest.

Aside from processor count, the new single-1.8GHz G5 Power Mac shares most of the dual-1.8GHz model’s specifications – the exception being a slower frontside bus speed. The frontside bus connects the processor to the system controller. It’s one of those tech specs that is rarely considered, but Macworld’s tests prove that it’s a vital performance determinant.

On the single-processor system, the bus speed is 600MHz – the same as the 1.8GHz G5 iMac (reviewed Macworld November 2004). Looking at the benchmark results below you’ll see that the new single-processor 1.8GHz Power Mac’s performance is right in line with the 1.8GHz G5 iMac.

As stated earlier, this is not the first time that Apple has offered a single-1.8GHz Power Mac. The previous model, at the time a higher-end rather than entry-level system, came with a 900MHz frontside bus, a larger hard drive, twice the RAM, and that £750-higher price tag.

In an attempt to isolate the frontside bus and processor, we took the drive and graphics card out of the new single-1.8GHz system and installed them into the older, faster bus 1.8. (Note: We test all systems with 512MB of RAM.) In these tests, the older, faster bus system beat the newer system in every task, though not by a wide margin. The difference in system speed really showed up in the Compressor MPEG-2 encode test with the 900MHz bus system finishing the task nearly 30 per cent faster than 600MHz bus system.

While this 1.8GHz Power Mac is easily beaten on certain tasks even by its immediate predecessor and thrashed when using multiprocessor-aware applications (such as Adobe Photoshop), it’s still a speedy performer. There are clear benefits to having two G5s in the box – overall, there’s an 18 per cent boost at the same chip speed – but there’s little difference when it comes to iMovie rendering for instance, and this system boasts better gaming juice than even its big dual-G5 brother.

As with all Apple systems, performance will be greatly improved by adding more memory. The 256MB installed as standard here is an insult to even Apple’s iLife consumer applications, let alone pro software. Apple charges £50 to boost this to 512MB – the bare minimum in our opinion – and £150 for a healthier 1GB of RAM.

Buy from a third-party memory reseller, however, and you can save cash while boosting RAM. Online we sourced an extra 512MB to take the system to 768MB for £60, and another 1GB to achieve 1.25GB of RAM for just £120. Hunt around for the best prices.


The message here is about value; the new Power Mac, at £1,099, is definitely a bargain. But it does appear that, when it comes to frontside bus speed, megahertz does indeed matter. The welcome return of the single-chip Power Mac G5 marries today’s performance to the upgradeability of the Power Mac enclosure. While the G5 iMacs are close on speed, there’s less flexibility in terms of swapping out video accelerators, or adding multiple internal drives and up to three expansion cards. If the options of adding internal extras or dual-display support are important to you, this new starter Power Mac is ideal. If not, consider a G5 iMac (which also saves you the considerable expense of buying a separate display). If you need top professional power, you should definitely buy a system with two processors.

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