Skip to content
Thoughtful, detailed coverage of everything Apple for 34 years
and the TidBITS Content Network for Apple professionals

Back to Class with the Power Mac G4

Apple’s announcement of the Power Mac G4 at last week’s Seybold San Francisco 99 took many by surprise – after all, the blue and white Power Mac G3 had been out for only nine months and rumors put more faith in the possibility of an enhanced iMac. But that ignores the massive influence of Apple’s interim CEO Steve Jobs, who loves to pull rabbit after PowerPC-based rabbit out of his hat at keynote addresses. Instead of sticking with the expected, Jobs wowed the audience with the snazzy silver and graphite Power Mac G4 and the stunning 22-inch LCD Apple Cinema Display. His timing was brilliant, given that he was largely talking to the design industry (the traditional Seybold audience), who especially appreciate Apple’s industrial design and who are known to buy the fastest Macs Apple releases immediately, since speed increases in applications like Photoshop translate directly to improved productivity.


The PowerPC G4 — The first Power Macintosh G4 systems start at speeds of 400 MHz, with upcoming models set to run at 450 MHz and 500 MHz. Overall, the G4 systems claim some performance specs nearly three times faster than 600 MHz Pentium III CPUs. The new systems are driven by the PowerPC G4 processor, which Apple is billing as the first supercomputer on a chip because it can theoretically offer sustained performance of more than a billion floating point operations per second – a spec called a "gigaflop." The PowerPC G4’s spectacular performance stems in part from its 128-bit "Velocity Engine" – formerly known as AltiVec. The G4’s Velocity Engine can perform multiple operations during a single clock cycle in parallel with traditional processor operations and has special capabilities for handling streaming media and transforming data. As with previous innovations in the PowerPC line, programs do not need to be recompiled to run on PowerPC G4 processors; however, programs will need to be recompiled to take specific advantage of the G4’s Velocity Engine. So, a typical application might see a 15 to 20 percent performance improvement running on a G4 system compared to a comparatively clocked G3-based Macintosh, but some applications recompiled for the Velocity Engine could perform some functions 2 to 8 times faster. A number of developers have announced support for G4 systems, including Macromedia, Adobe, Terran Interactive, Casady & Greene, and Bungie Software.



< 31developer.html>

PCI versus AGP — The specifications for the Power Mac G4 systems aren’t anything to sneeze at either, offering a 100 MHz system bus, 1 MB of Level 2 backside cache, 64 to 256 MB of RAM, three 64-bit PCI slots, 10/100Base-T Ethernet, 10 to 27 GB hard disks, 32x CD-ROM or DVD drive options, an ATI RAGE 128 video card with 16 MB of VRAM, FireWire, and two USB ports. Like Apple’s blue and white Power Mac G3s, the Power Mac G4 systems come in minitower cases with easy internal access and do not include a floppy disk drive; however, the G4 systems lack the blue and white’s ADB port and come in a more muted translucent white and graphite color scheme, perhaps responding to many Macintosh users’ concerns over the comparative gaudiness of the iMac color palette.


Unfortunately, once you digest those specifications, the confusion begins. Apple has developed two versions of the Power Macintosh G4, dubbed "PCI Graphics" and "AGP Graphics" – AGP stands for Advanced Graphics Port. The PCI Graphics G4 is essentially a souped-up version of the existing blue and white Power Macintosh G3 architecture, minus the ADB port but adding a 100 MHz system bus and the PowerPC G4 processor. The PCI Graphics G4s will ship in 400 and 450 MHz configurations; the 400 MHz versions are available immediately, with the 450 MHz versions to follow in October. Using the existing motherboard design enabled Apple to ship PowerPC G4-based systems at low prices – right now, 400 MHz PCI Graphics G4s currently start at $1,600, the same price as the 400 MHz G3 systems they replace.

The AGP Graphics G4’s, codenamed Sawtooth, are built on a redesigned motherboard which offers a host of improvements over the "Yosemite" motherboard architecture introduced with the blue and white Power Macintosh G3s. Key enhancements include:

  • 128-bit internal memory data paths
  • Support for Ultra ATA/66 hard drives (about 50 percent faster than PCI Ultra ATA/33 drives in earlier systems)
  • Separate 12 Mbps USB controllers for each USB port, rather than having both ports share a single 12 Mbps controller – making more USB bandwidth available to peripherals
  • A new Open Host Controller Interface (OpenHCI) chip controlling the FireWire subsystems, offering more efficient performance and larger data buffers
  • Enhanced PCI bus performance (up to 50 percent faster than earlier designs)
  • Optional support for AirPort wireless networking
  • Optional digital video input
  • DVD decoding in software (rather than in hardware)
  • The standard ATI RAGE 128 video card ships in an AGP 2x video slot, rather than in a modified PCI slot.

AGP is a graphics standard from the PC world: Intel developed it from PCI, and PCs with AGP slots began to appear in 1997. AGP caters to the high-throughput demands of 3D graphics, and enables 3D textures to be stored in the computer’s main memory rather than in video memory. AGP Graphics G4s include an AGP 2x slot, which can theoretically deliver 533 megabytes per second (MBps) throughput to the screen. AGP 4x is faster still, pushing just over 1 gigabyte per second (GBps) to the screen. AGP is particularly interesting to developers bringing graphics-intensive applications to the Macintosh using OpenGL.


Still with us? Hold on tight: the differences between PCI Graphics G4s and AGP Graphics G4s don’t stop there. AGP Graphics systems can optionally include a unique 56 Kbps modem with the DSP card on the system’s motherboard, but with the Digital to Analog (D to A) converter connected to the rear case. If a system doesn’t ship with a modem, it won’t have the DSP card on the motherboard, but will still have a D to A converter on the rear case, mounted so the phone jack doesn’t show.

In addition, AGP Graphics G4s sport a PowerBook-style sleep mode which turns off the PCI cards and the computer’s fan – a welcome addition to a desktop Mac. When asleep, the AGP Graphics G4s consume just 6 watts of electricity – less than a typical night-light. Considering that computers typically consume 3 to 5 watts of power even when they’re turned off (trickle-feeding their batteries, etc.), there’s almost no need to shut down an AGP Graphics G4 except to add or remove internal hardware – especially since USB and FireWire external devices are hot-swappable. To support this feature, PCI boards must support Apple’s Power Manager 2.0 (software built into the Mac OS). If a board doesn’t support Power Manager 2.0, the system will still go to sleep but will have to leave the fan on to cool the PCI board, thus consuming more power.

Just one more thing: a special version of Power Mac G4 will be available from the online Apple Store that ships with a digital video connector specifically for use with the just-announced (and pricey) Apple Cinema Display (see below). If you were thinking about using the Apple Cinema Display with a different computer, think again, since you can’t.

If you’re excited about these new AGP Graphics G4 systems, don’t work yourself into a lather yet: while the systems are set to ship with 450 and 500 MHz G4 processors, they aren’t expected to be available from Apple until November at prices ranging from a bare-bones $2,400 all the way to $6,500 for a 450 MHz system with the new Apple Cinema Display.

Riddle Me This — One dark spot in the otherwise glowing details about the Power Mac G4 is the name – Apple is shipping two radically different computers and calling them the same thing. Adding to the trouble, the machines will have nearly identical appearances: if you want to tell the difference between a PCI Graphics G4 and an AGP Graphics G4, you may have to get down on your hands an knees and crawl under your desk. The only visible difference is on the back panel: PCI Graphics G4s orient sound and video input jacks horizontally; AGP Graphics G4s orient them vertically.

< n58418>

This naming insanity reportedly comes directly from Steve Jobs, and although it’s a good marketing move, it is causing problems for tech support staffs and for consumers trying to purchase appropriate upgrades and peripherals. Our suggestion of a coherent version numbering scheme outside of the marketing name would address the naming confusion without diluting the marketing force of a single name, and we continue to encourage Apple to adopt this or a similar naming scheme (see "Macintosh Model Implosion: What’s in a Name?" in TidBITS-485).



Blue & White G4s? If you’re thinking about upgrading a recently purchased blue and white Power Macintosh G3 to a G4 processor, you might have to wait a while. Although vendors such as XLR8, Sonnet, and Newer Technology have already announced G4 upgrades for a variety of PCI-based systems and "beige" G3s, Apple’s G3 Firmware Update 1.1 for blue and white Power Mac G3s (announced as improving PCI performance) also included a change which prevents the machines from starting up if a G4 processor is installed. Apple has never advertised any G3 system as being CPU upgradable, but Apple’s unannounced decision to disable G4 processors in blue and white G3s has angered a number of customers. Apple may have made the firmware change for quality-control purposes or to avoid having its thunder being stolen by third-party upgrade vendors, but it’s also important to remember that Apple’s recent financial recovery has been fueled by new hardware sales, not by CPU upgrades to older machines. Enterprising CPU upgrade vendors may well work around Apple’s firmware restriction, however.




< n11361>

Power Mac G4 Colors — In "A Case for Color" in TidBITS-492, we wrote, "If Apple wants to gain the good graces of the business market, they’ll have to figure out a Macintosh design compromise that fits in while standing out, much as wearing an expensive Italian suit might do for an individual." The Power Mac G4, with its polished silver and graphite colors applied to the curvy case introduced by the blue and white Power Mac G3, would seem to meet the needs of the business world while maintaining its individuality.


Whether or not the community actually uses the canonical color name of "graphite" remains to be seen. Although it’s certainly easier to say "gray," graphite connotes drawing pencils, and thus a nod to traditional art and design. Of course, before the blue and white Power Mac G3, Apple officially referred to its desktop machines as "platinum," whereas everyone knew them as "beige."

Apple has updated the plastics on the Apple Studio Display monitors to match the Power Mac G4’s graphite color scheme, and the Apple Cinema Display sports a clear enclosure that goes with the new Power Mac G4 look. Users upgrade monitors much less frequently than computers, so it would make sense for Apple to move towards a more neutral look that would match both the current blue and white Power Mac G3 and the new Power Mac G4.

AirPort Support — When we wrote about the iBook and Apple’s AirPort wireless networking (which has yet to ship) back in "iBook: An iMac to Go" in TidBITS-490, we commented "that within a year, we’ll see AirPort antennas available across Apple’s entire line." The announcement of the optional AirPort wireless networking support in the Power Mac AGP Graphics G4 models points to Apple’s commitment to including AirPort across the line. In Apple’s four-cell product matrix, the remaining cells whose machines lack AirPort support are the consumer desktop iMac and the professional portable PowerBook G3, so look for the next releases of those machines to include the necessary circuitry to add AirPort networking.


Apple Cinema Display Packs in the Pixels — Last, but certainly not least, Apple also announced the Apple Cinema Display, a ground-breaking 22-inch thin film transistor (TFT) active-matrix LCD display. The all-digital monitor, which Apple claims is the largest LCD display to reach market, has an active viewing area equivalent to a 24-inch CRT monitor, with a native resolution of 1,600 by 1,024 pixels at 16.7 million colors, enough to display two full pages of text or full-screen DVD movies without letterboxing. Not surprisingly, Apple expects supplies of the hard-to-manufacture display to be extremely limited when it ships in October or November (depending on which Apple Store page you believe), so at least initially it will be available only through the Apple Store and only with a 450 MHz Power Macintosh G4 (and its ATI RAGE 128 Pro graphics card) for $6,500. Considering its price tag of $4,000 if sold separately ($2,500 more than Apple’s 21-inch CRT-based Apple Studio Display), the Apple Cinema Display is not yet a display for the rest of us, though it has a tremendously high lust factor.

The prices on the Power Mac G4, though, make it difficult for those of us who often wait until the end of a product’s lifespan to buy so as to pick up the most performance at the lowest price. Although we haven’t seen an official statement, it seems the entire Power Mac G3 line has been replaced by the Power Mac G4. However, Apple’s dramatically improved inventory control means that there probably aren’t many Power Mac G3s available after the current bunch in the channel sell out. And the low pricing on the Power Mac G4 means that it may be more worthwhile to buy into new technology rather than looking for a deal on yesterday’s Macs.

Subscribe today so you don’t miss any TidBITS articles!

Every week you’ll get tech tips, in-depth reviews, and insightful news analysis for discerning Apple users. For over 33 years, we’ve published professional, member-supported tech journalism that makes you smarter.

Registration confirmation will be emailed to you.

This site is protected by reCAPTCHA. The Google Privacy Policy and Terms of Service apply.