Power Macintosh G5


After a long wait, Macworld Lab got its hands on a new dual-2.5GHz Power Mac G5. We compared the relative performance merits of all Apple’s pro workstations; however, we didn’t have time to complete our exhaustive Speedmark benchmark on the new top-end system, which we’ll present in the next issue. We Speedmarked the lower-end models – the 1.8GHz dual-processor (DP) and 2GHz DP configurations – to see how their performance stacks up against the previous 1.8GHz DP machine.

Apple was uncharacteristically optimistic and open about future G5 speeds, which backfired on it when chip-maker IBM failed to reach the promised 3GHz figure this summer. The original G5 chip architecture was 130 nanometres wide, but the new range is based on an even smaller 90-nanometre set. Analysts blame this change in manufacturing process for the failure to hit 3GHz on schedule, and that meant we’ve had to wait until now for the full G5 range to become available.

In switching to 90 nanometers, the industry has had more problems raising the clock speed than anyone anticipated. Intel has cranked up only a couple of hundred megahertz from 3.2GHz to 3.4GHz. So, IBM gets a round of applause for being able to crank the chip up from 2GHz to 2.5GHz – a 25 per cent increase.

The real damage will be done if people decide to skip 2.5GHz and wait for the promised 3GHz. However, some analysts now don’t expect IBM to reach the 3GHz target for another year. If you need to upgrade now, waiting around for a 3GHz G5 means you’ll be underpowered for a long time. Anyone holding onto a Power Mac G4 in wait for the 3GHz should jump to G5 right now.

Top-end tower We used the Xbench benchmark on the top-end 2.5GHz Power Mac G5. The results point to an 18 per cent overall speed advantage over the 2GHz DP and a meaty 30 per cent gain on the 1.8GHz DP. This whopping performance boost – which required Apple to create a special liquid-cooling system for the 2.5GHz DP – makes the extra outlay well worth the money for any graphics, video or music creative pro. But for many the £750 saving on the entry-level Power Mac would be better spent on extra RAM or upgrades to Adobe Creative Suite, for instance.

Battle below As Macworld Lab tests prove, the £400 difference between the entry-level and mid-range systems doesn’t make much sense in some applications. There’s a 9 per cent overall speed jump, but in iMovie rendering, MPEG-2 encoding for Web streaming and DVD, and even our suite of tough Photoshop tasks, the performance gap is minimal. The 2GHz DP system supports twice as much memory (up to 8GB), so if you’re big on RAM this model may make sense. You also get twice as much hard-disk space and double the installed RAM – but a 1.8GHz DP could be equipped with an extra 250GB disk space (£200) and 1.2GB
of RAM (£120) and still leave you with spare change.

Aside from the amount of installed memory and the size of the hard drive, the specs for the dual-1.8GHz G5 unveiled in June 2004 and the one introduced in November 2003 are nearly identical. And, as you’d expect, so are the Speedmark numbers. (We installed 512MB RAM in each system.)

Last year’s dual-1.8GHz model cost £1,899, while this year’s is priced at £1,449 (though Apple charges £50 for an extra 256MB of RAM). The newer, less-expensive dual-1.8GHz system performed as well as expected, with a few exceptions. The instances where the older system out-performed its seemingly identical replacement are probably due to the differences in hard drives.

As the previous mid-range model, the older dual-1.8GHz model came with a roomy 160GB Seagate Barracuda hard drive; the newer entry-level model features an 80GB version of the same drive. The drive swap seems to have sacrificed speed as well as storage capacity – note the older model’s faster times in several of our tests. In fact, the older 1.8GHz DP even bested the 2GHz DP (featuring a Maxtor DiamondMax 160GB drive) in disk-intensive actions, such as file duplicates and video encoding – although just by a hair.

Find the best price