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Apple Announces 64-Bit Power Mac G5s

Touting them as the "world’s fastest personal computer," Apple today announced its Power Mac G5 line of desktop computers with 1.6 to 2 GHz processor speeds, high-performance internals, and a 64-bit processor architecture designed to give the Power Mac line a much-needed performance boost and provide a clear road map for future development. Standard configurations of the new machines are priced from $2,000 to $3,000, and will be available starting in August of 2003.


Out of the Wind Tunnel, On to the Cheese Grater — On the outside, the Power Mac G5 establishes yet another direction in Apple’s industrial design, this time sporting an anodized aluminum case with squared-off handles and perforation on the front and back to permit airflow through the machine’s four internal "thermal zones." (The new design has already been dubbed the "cheese grater," and the resemblance is remarkable.) The units have no less than nine internal fans, yet Apple says in normal operation they’re substantially quieter than earlier Power Mac G4 (Mirrored Drive Door) systems that were not-so-affectionately nicknamed "Windtunnels." As you’d expect, the Power Mac G5 enclosures feature a full complement of ports on the back, but also offer USB, FireWire, and headphone jacks on the front, which may save some crawling around under desks.


The G5’s Alive — The real changes are inside the box. The Power Mac G5 systems are built around the 64-bit IBM 970 processor, which Apple has dubbed the PowerPC G5. The PowerPC G5 evolved from IBM’s POWER4 architecture (used in the company’s high-end eBusiness servers), rather than directly following from G3 and G4 processors developed by Motorola. However, if the PowerPC G5 isn’t a direct descendent of the processors in current Macs, it’s a cousin: the original PowerPC architecture was designed jointly by Apple, Motorola, and IBM, and was meant from the outset to be expanded to a 64-bit architecture. Eventually, IBM branched off with what became the POWER4 architecture when it decided it wanted to focus on processor clustering, servers, and embedded systems, and Motorola came up with the high-output AltiVec unit (aka Apple’s Velocity Engine). The PowerPC G5 weds the two efforts, combining IBM’s POWER4 architecture with an optimized Velocity Engine and a new 130-nanometer manufacturing process at IBM’s new plant in Fishkill, New York.


Here are the main features of the PowerPC G5:

  • High clock speeds: PowerPC G5s start at 1.6 to 2 GHz , and Apple says 3 GHz G5s will be ready within a year.

  • A 64-bit architecture enables Macs to handle up to 8 GB of RAM initially, with a real-world RAM ceiling of 4 terabytes (TB).

  • Full compatibility with existing 32-bit PowerPC software – i.e., everything which runs right now under Mac OS X, including Classic applications and the Unix environment. Existing applications can run on the new processors with no penalty – no emulation or recompiling required – and current applications optimized for the Velocity Engine garner an instant speed bump. Programs recompiled specifically for the PowerPC G5 processor will see even greater performance enhancements.

But wait, there’s more. One of the problems with modern personal computing architecture is that processors spend a surprising amount of time twiddling their thumbs waiting on other parts of the computer like RAM, the PCI or FireWire buses, or (horror of horrors!) a mere disk drive. Processors engage in branch prediction (er, idle speculation?) while they’re waiting so they’ll be ready to go when a computer’s subsystems catch up, but basically, you want the processor waiting around as little as possible. To that end, Apple has put nearly every major subsystem in the Power Mac G5 on its own high-speed bus (avoiding traffic jams as data moves between components: RAM gets a 333 or 400 MHz bus, PCI-X cards get a 133 MHz bus, etc.) and – most significantly – a separate pair of 32-bit unidirectional buses for the G5 processor running at speeds from 800 MHz to 1 GHz. Combined, these are termed a frontside bus, and they represent a substantial leap forward from the 167 MHz system buses used in previous high-end Power Mac G4 systems, and – even better – dual processor G5 systems have a separate frontside bus for each processor, further enhancing performance on dual processor machines.

Apple’s Top Models — Apple will be shipping three configurations of the Power Mac G5 beginning in August. All configurations can handle Bluetooth and Airport Extreme wireless networking and feature 8x AGP Pro graphics slots, a Serial ATA hard drive, 512K of L2 processor cache per processor, 4x SuperDrives, one FireWire 800 port, two FireWire 400 ports (one on the front), three (new!) USB 2.0 ports (one on the front), two USB 1.1 ports (one on the keyboard), two internal hard drive bays (one empty), built-in Gigabit Ethernet, a 56 Kbps V.92 modem, analog and (new!) optical audio in and out, and a front headphone jack. These systems boot into Mac OS X, and cannot start up from Mac OS 9 (although, of course, the Classic environment is still available within Mac OS X).

The low-end $2,000 model features a 1.6 GHz PowerPC G5 processor with an 800 MHz frontside bus, 256 MB of PC2700 (333 MHz) RAM, an Nvidia GeForce FX 5200 Ultra video card with 64 MB of video RAM, an 80 GB hard drive, and three available full-length 33 MHz, 64-bit PCI slots. The mid-range $2,400 model has a 1.8 GHz PowerPC G5 processor with a 900 MHz frontside bus, 512 MB of PC3200 (400 MHz) RAM, an Nvidia GeForce FX 5200 Ultra video card with 64 MB of video RAM, a 160 GB hard drive, and three available full-length 64-bit PCI-X expansion slots (one at 133 MHz, the other two at 100 MHz). The $3,000 high-end system features dual 2 GHz PowerPC G5 processors with a 1 GHz frontside bus for each processor, 512 MB of PC3200 (400 MHz) RAM, an ATI Radeon 9600 Pro with 64 MB of video RAM, a 160 GB hard drive, and three full-size 64-bit PCI-X expansion slots (one at 133 MHz, the other two at 100 MHz).

Each of these configurations can be customized using build-to-order options through dealers, Apple Stores, or the online Apple Store.

Five and Dime — There’s no doubt that, when they finally become available in late summer, the Power Mac G5s will represent a substantial performance improvement for Apple’s aging Power Macintosh line – no doubt many Macintosh proponents have already placed their orders for these machines. Significantly, the PowerPC G5 processor and the new system architecture give Apple room to grow: expect to see more multi-processor systems become available as the product line evolves, along with concomitant speed increases in processors, frontside caches, and other internal components.

It remains to be seen how transparent developers will be able to make the transition to the PowerPC G5. High-end media applications and action games will want to compile specifically for the PowerPC G5. Hopefully, programmers will find a way to make PowerPC G5 versions of their programs available without creating confusion amongst existing and future PowerPC G3 and G4 users, particularly since Apple’s laptop line may be using G3 and G4 processors for some time to come.

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