display | more...

The Power Macintosh G5 is the latest in Apple's "Pro" line of computers. The system architecture of previous Power Macs hadn't changed much in recent years, but the Power Mac G5 is a radical departure from the previous design.

Shiny

You can say what you want about Apple's machines being too expensive and too slow or their operating system being rubbish, but what you can't deny is the quality of their design. Products like the iPod, the titanium (and now aluminum) powerbooks just ooze quality. You can tell that unlike most manufacturers, Apple pays attention to the appearance and packaging of its computers. The G5 is no exception.

The box is black, with G5 in large silvery letters on two sides, a picture of the front and back of the computer on two other sides with the remaining 2 sides being just plain black. After opening the box you are greeted by a sheet of cardboard with a side view of the computer, with the words "Designed by Apple in California" in small print at the bottom left. Beneath this is the usual polystyrene tray with keyboard, mouse, CDs, documentation and cables. Below this lies the beast. This isn't a flimsy, hastily put together job, it's 18kg of hefty aluminum goodness. The design is minimalist, with sleek curves and generally feels and looks great.

All too often, when opening a computer one finds a jungle of cables. Not only do these look bad, but they often impede the flow of air through the machine. Opening a G5 is an easy job, simply pull a lever at the back of the machine and the side panel unlatches. Not a power or ribbon cable in sight! Everything is carefully tucked away (and with Serial ATA ribbon cables are a thing of the past). A strangely shaped piece of transparent plastic still lies between you and the innards of the machine. This piece of plastic helps keep air flowing through the machine as Apple intended, aided by no less than 9 fans.

Numbers and stats(Initial version)

  • Processor: Choice of one 1.6 Ghz or dual 1.8Ghz or dual 2 Ghz G5 processors (a.k.a PPC 970) with 512kb of L2 cache per processor. Each processor is connected to the system controller by an independent 64 bit (32 bits in each direction) bus running at half the frequency of the processor, yielding throughput of up to 8Gbps per processor. The dual 1.8 Ghz model replaces an earlier single processor 1.8 Ghz model.
  • Optical drive: "Superdrive": DVD-R/CD-RW drive (a Pioneer 106D in mine)
  • Expansion: 1 64bit PCI-X slot @133 Mhz, 2 64bit PCI-X slots @100Mhz (the 1.6 Ghz model only has normal 64 bit 33Mhz PCI slots), 1 8x AGP Pro slot.
  • Connectivity: 3x USB 2.0, 2x Firewire 400, 1x Firewire 800, Analog audio in/out, Optical (tos-link) audio in/out, gigabit ethernet, Bluetooth (optional), Airport Extreme (optional), modem. The front panel has USB, Firewire 400 and headphone connectors.
  • Memory: Dual channel DDR 400 (DDR 333 for the 1.6 Ghz model), 8 slots for up to 8 GB of memory (4 slots and a maximum of 4 GB for the 1.6 Ghz model).
  • Storage: Two internal hard drive bays, connected via Serial-ATA. Standard configuration is a single 80 or 160 GB 7200 rpm drive.
  • Video Card: Choice of GeForce FX 5200, Radeon 9600 Pro or Radeon 9800 Pro.
On June 9, 2004, Apple updated their lineup. The available models are now dual 1.8Ghz, dual 2Ghz and dual 2.5Ghz. The fastest version features a new liquid cooling sysem. As before the slower model has 4 memory slots and 3 PCI slots, whereas the 2 faster ones have 8 memory slots and 3 PCI-X slots. Other small changes have been made, such as XT versions of the Radeon cards being used and the superdrives are now officially 8x.

This is a significant overhaul compared to previous models. Whereas the Power Mac G4 had a very bandwidth challenged architecture (167 Mhz SDR FSB (shared by both processors when applicable)) the Power Mac G5 has got oodles of it. The architecture is based around the use of multiple HyperTransport buses. This is also the first Macintosh to support surround sound, via the use of its optical audio ouput.

Compatibility issues

The most significant issue is for users of PCI cards. PCI cards can operate at either 3.3V or 5V, but only 3.3V cards can be used in a PCI-X slot. Obviously such PCI cards will only operate at their normal speed. The 2 100Mhz slots share a single bus, and if a PCI card is placed in one of these slots then both will operate at normal PCI speeds, but the third slot will not be affected (and vice-versa). Users of expensive audio/video editing cards may need to renew their equipment, unless they go for the 1.6 Ghz model.

Although the G5 is a 64bit processor, it is fully compatible with existing code, although obviously applications optimized specifically for the new processor will have an extra performance increase. The single exception to this (as far as I know) is Virtual PC. This software used a feature of G3 and G4 processors known as "pesudo little-endian mode" which is not present in the G5. Microsoft is said to be working on fixing this.

Another concern is the loss of parallel ATA, as many users may have hard drives they wish to carry over to their new systems. Apple have explicitly stated that serial to parallel adapters will not work, however people have managed to connect their drives to the ATA bus that the optical drive is on.

Performance

Obviously, this is what many people are most interested in, but it is also one of the hardest to quantify. The Power Mac G5 is significantly faster than its predecessors, and has oodles of bandwidth sloshing about. But when it comes to hard figures, well, as they say, there are lies, damn lies and benchmarks. Apple has published figures claiming that their systems beat Intel systems, and there have been lengthy discussions about how good the compilers were, whether they were using things such as SSE or Altivec and so on. An article was published comparing Adobe Premiere, and in those tests the G5 lost quite badly. This isn't entirely surprising and a curious choice of benchmark, as Adobe has ceased developing Premiere for the Mac (and users have ceased using it, choosing Final Cut Pro instead), and the current version still runs in Classic.

At the end of the day, a benchmark is just a number, what matters is the software you will be running. Will it be optimised for the G5 and/or multiple processors? Some applications will get greater benefits from the processor's 64 bit capabilities than others, what do you need? Whether or not you believe Apple's figures, the Power Mac G5 is definitely not to be laughed at. Virginia Tech recently bought 1100 dual processor G5s for their "Big Mac" cluster.

Noise

A significant complaint with many recent machines is the noise made by the fans needed to dissipate all the watts belched out by processors and the like. Apple's previous G4 line had been nicknamed "wind tunnels" and Apple eventually gave in and shipped quieter power supplies to all owners who wanted one. The G5 on the other hand is designed to be quiet. Specially designed low rpm fans are used throughout the system. Both the front and the back of the casing are perforated, helping air to flow freely, cool air being sucked in at the front and warm air ejected at the back. The speeds of 7 of the 9 fans are adjusted independently as needed by the system, to keep noise at a minimum.

The system is divided up into distinct thermal zones, each of which is cooled independantly. The plastic deflector ensures that air flows over the parts of the system that needs cooling (mainly the processor heat sinks, serviced by a total of 4 fans) and the PCI and AGP slots. In use the Power Mac G5 definitely classifies as a quiet machine when compared with other machines I have used, although noise levels do increase with processor load. When the machine is used in target disk mode, the software controlling the fans does not run, and so all fans run at maximum speed which makes the machine sound as if it is about to take off (this also happens if the case is opened and the plastic deflector removed).

The Power Mac G5 ends the G4 debacle and provides a well needed renewal of Apple's Pro line. I have just bought one and it is one sweet sweet machine.

Sources:
http://www.macworld.co.uk/news/main_news.cfm?NewsID=6792
http://www.apple.com/powermac
A few days days with my precious...

Log in or register to write something here or to contact authors.