Power Mac G4

Released : August 1999 (PCI), September 1999 (AGP), July 2000 (Gigabit Ethernet), January 2001 (Digital Audio)

Price: $1,599 – $3,499

Acquired: September & October 2011 (Craigslist, friend)

Cost: FREE 

About the Machine

Only eight months after the Blue and White G3 debuted Apple announced the Power Mac G4.  It was the first Mac to use Motorola’s PowerPC 7400 processor – capable of up to four gigaflops of performance – classifying it as a supercomputer.  The Power Mac G4 uses the same case as its G3 predecessor but replaces the playful teal color with a shade of gray dubbed “Graphite”.  The frosted plastic on the handles and sides of the case has been replaced with glossy clear plastic and the “G3” silkscreening on the side  has been removed entirely. Otherwise the case is exactly the same as the G3 – same number of drive bays, same expansion door, same number of PCI slots, same power supply, etc.

The Power Mac G4 is the first Mac to use Motorola’s PowerPC 7400 processor, branded as the G4 by Apple.  The PowerPC 7400 shares a similar design with the Power PC 750 (G3) but includes larger and faster caches, supports multiprocessor configurations, and includes a vector processing unit called AltiVec.  AltiVec is the major selling feature of the 7400 and thus the Power Mac G4 line.  Branded the Velocity Engine by Apple, AltiVec accelerates common graphics and media routines.  This unit is similar to MMX on the x86 platform, but provides better performance. Software written to take advantage of the Velocity Engine (such as Photoshop) sees large gains on the G4, while non-optimized software performs only marginally better than it would on a G3 at the same speed.  Portions of Mac OS X are actually optimized for the Velocity Engine, allowing Apple’s bread and butter software platform to run generally better on a G4 than it does on a G3.  A fun fact – Mac OS 10.5 Leopard, the last version of OS X available for Power PC Macs, can’t even run on a G3 because it doesn’t have the Velocity Engine.

Models

The original Power Mac G4 design spanned four revisions from 1999 through 2001.  The first revision was based on the same motherboard as the outgoing Blue and White G3.  Apple essentially slapped a G4 processor onto a G3’s PCI motherboard. The original G4’s based on the PCI motherboard (code named “Yikes”) offered limited performance benefits over a G3 because the motherboard couldn’t move the data around fast enough. The PCI motherboard was limited to the 400 MHz (and later 350 MHz) models.

The 450 and 500 MHz models were based on a brand new AGP motherboard (code named “Sawtooth”) that provided a faster interface for the processor and faster graphics. These were the models that allowed the G4 to really shine.  In addition to a new motherboard , these models also featured individual USB busses for better device performance, a slot for an optional AirPort wireless networking card, and the ability to boot off of a FireWire drive. In July of 2000 the G4 was updated to include Gigabit Ethernet networking  and introduced dual CPUs back into the Macintosh line, the first time since the Power Macintosh 9600 was introduced in 1997. Unfortunately a dual 500 MHz G4 was as good as it would get for the next ten months as Motorola struggled to manufacture G4 CPUs that could reliably run above 500 MHz.

The final update to the original G4 came in January 2001 with the introduction of the Digital Audio model.  With it Motorola finally broke the 500 MHz barrier, allowing Apple to include up to two 733 MHz G4 processors.

Trouble in Paradise

Ever since the first PowerPC Macs were released in 1993, Apple sourced CPUs from both Motorola and IBM.  This continued through the G3 era but stopped with the introduction of the G4.  IBM didn’t see the need for AltiVec and chose not to manufacture it on their chips. Since Apple depended on it, this left Motorola as their only option.  Issues became evident quickly with the release of the first Power Mac G4s.  They went on sale with 400 MHz and 500 MHz processors, but Motorola had trouble manufacturing enough chips that could run reliably at those speed. A few months later, the speed of all of the CPUs was lowered by 50 MHz with no change in price. It caused quite a stir in the Apple community.  A 50 MHz drop was anywhere from a 10% – 12% drop in raw performance without any compensation.

Once Motorola was able to produce G4 processors reliably at 400 MHz and 500 MHz, they had trouble scaling.  Chips running at speeds higher than 500 MHz ran hot and failed often, so often that Motorola couldn’t even deliver them to Apple for inclusion in the next G4 revision. The original line of G4s was getting old and Apple had to release something. So they decided to take advantage of the G4’s multiprocessor support and start including two CPUs in each Mac. This didn’t quite double performance (especially in Mac OS 9), but it provided enough of a boost to remain competitive.

It took Motorola a year and a half to break the 500 MHz barrier, releasing a 733 MHz G4.  By that time Intel had already broken the 1 GHz barrier and was selling a 1.5 GHz Pentium 4.  The G4 never really caught up, maxing out at 1.67 GHz by the time Apple switched to Intel in 2006.

My Collection

The first G4 Mac that I owned was my 12″ PowerBook. I never owned a G4 tower but always wanted a G4 machine because it ran Mac OS X better.  Now I have two of them, three technically, but one has been harvested for parts to build the other two.  My two working G4 towers are a 400 MHz Sawtooth model and a 500 MHz Gigabit Ethernet model. Both have a DVD drive, a 16 MB ATI Rage 128 Pro graphics card, and Zip 100 drives.  The Gigabit model also has an Airport card for wireless networking. An interesting fact about my Gigabit Ethernet model is that it has a single 500 MHz G4 processor in it.  The Gigabit Ethernet models never shipped with a single 500 MHz G4 – I took the CPU out of my non-working G4 as the processor sockets and motherboards between the Gigabit and Sawtooth models are almost exactly the same.

I run a host of Mac OS versions on my G4s.  Since I don’t use them for daily work I’m more interested in seeing the difference in features and performance of the various versions of the Mac OS.  As such, I’m running every version I can – Mac OS 9.22, 10.0, 10.1, 10.2, 10.3, 10.4, and even 10.5 (an unsupported install that doesn’t happen to boot correctly). My Gigabit G4 is attached to a 17″ Apple Studio display, in graphite.  I’m actually quite impressed with the quality of the display – it is far sharper than the displays on any of my 15″ iMacs and has a higher max resolution than my 17″ eMac – 1600 x 1200 – the same as the 21″ model and slightly more than the 22″ Apple Cinema Display.

Tech Specs
	PCI	AGP	Gigabit Ethernet	Digital Audio
Processor	350 or 450 MHz PowerPC 7400 (G4) with 512k or 1MB L2 Cache	350, 400, 450, or 500 MHz PowerPC 7400 (G4) with 1MB L2 Cache	Single 400, Dual 450, or Dual 500 MHz PowerPC 7400 (G4) 1MB L2 Cache	Single 466, 533, Dual 533, 667, or 733 MHz PowerPC 7400, 7410, or 7450 (G4) with 256k or 1MB L2 Cache, 1 MB L3 Cache (733 MHz)
Memory	64 MB PC 100 SDRAM	128/256 MB PC-100 SDRAM		128/256 MB PC-133 SDRAM
Hard Drive	10 GB Ultra ATA/33	10, 20, or 27 GB Ultra ATA/66	20, 30, or 40 GB Ultra ATA/66	30, 40, or 60 GB Ultra ATA/66
Other Drives	32x CD-ROM, optional Zip 100 drive	32x CD-ROM, 5x DVD-ROM, DVD-RAM, optional Zip 100 drive	DVD-ROM or DVD-RAM, optional Zip 100 drive	DVD-ROM, CD-RW, DVD-RW SuperDrive, optional Zip 250 drive
Video Card	ATI Rage 128 w/ 16 MB	ATI Rage 128 Pro w/ 16 MB	ATI Rage 128 Pro w/ 16 MB or ATI Radeon w/ 32 MB	ATI Rage 128 Pro w/ 16 MB, ATI Radeon w/ 32 MB, NVIDIA GeForce 2 MX w/ 32 MB, or NVIDIA GeForce 3 w/ 64 MB
Screen	NONE
Speakers	NONE
Expansion Slots	4 PCI – 3 @ 33 MHz, 1 @ 66 MHz (for graphics card)	4 PCI – 3 @ 33 MHz, 1 AGP 2X (for graphics card)	4 PCI – 3 @ 33 MHz, 1 AGP 2X (for graphics card)	4 PCI – 4 @ 33 MHz, 1 AGP 4X (for graphics card)
Ports	10/100 Ethernet, 56k modem, 2 USB, 2 FireWire 400, 1 VGA, Audio In, Audio Out	10/100 Ethernet, 56k modem, 2 USB, 2 FireWire 400, 1 VGA, 1 DVI, Audio In, Audio Out	10/100/1000 Ethernet, 56k modem, 2 USB, 2 FireWire 400, 1 VGA, 1 ADC, Audio In, Audio Out	10/100/1000 Ethernet, 56k modem, 2 USB, 2 FireWire 400, 1 VGA, 1 ADC, Audio Out, Apple Pro Speaker

Performance
	PCI	AGP	Gigabit Ethernet	Digital Audio
Geekbench	N/A	236 (350 MHz), 221 (400 MHz), 289 (450 MHz), 353 (500 MHz)	261 (Single 400 MHz), 418 (Dual 450 MHz), 500 (Dual 500 MHz)	314 (466 MHz), 352 (533 MHz), 542 (Dual 533 MHz)
XBench	N/A
Speedometer	N/A