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Review: Newer Tech's iMAXpowr G4/433 CPU Upgrade
World's First G4 CPU Upgrade for iMac 233 - 333MHz models
By Mike
Published: 7/19/2000
Intro | Benchmarks | Appl/Game Tests | Software Controls | Installation | Specs/Design | Summary

Pros: World's first iMac G4 CPU upgrade. System was 100% stable during extensive tests and provided a dramatic boost over the original CPU (see apps/games test results). Claimed to be OS X compatible. [OS X not released at time of review.] Includes video tape with step-by-step installation guide.

Cons: Due to the nature of the iMac case design, installation is not as easy as other Mac models. [Note: In early 2001, Newer Tech closed so there is no warranty support for their upgrades now. The iMac G4 upgrades were rare and are literally impossible to find now.]

OS Upgrade Notes: According to a reader report after OS 9.1 was released, applying the firmware update for the iMac for OS 9.1 resulted in the mezzanine slot no longer being recognized. This means that mezzanine slot cards like the Voodoo2 game wizard installed in this review system would no longer be used. (OS 9.1 is required for OS X and note there's no OS X support for 3dfx cards like the Voodoo2. Also note if you've upgraded your iMac hard drive, OS X must be installed on a partition fully contained within the first 8GB of the hard drive.)

Newer Technology's iMAXpowr G4 CPU upgrade does what many may have thought we'd never see - allow iMac rev A through D (G3/233 to G3/333MHz models) owners to upgrade their CPU to a G4 reliably. Benchmark and Applications/Game performance was dramatically boosted after installing the iMAXpowr G4 upgrade. The final price of $549 (July 2000) depends upon the return shipping of the original processor to Newer Technology within fourteen days. Newer expects the supply of these upgrades to be limited to 500 units per week.

About G4 CPU Performance:
As mentioned in my previous G4 reviews, without software that takes advantage of the Altivec core, a G4 runs applications no faster than a G3 CPU of the same speed (all other factors being equal). This is clearly shown on the Applications Tests page of this review. Buy a G4 upgrade or system for the benefits you will see with Altivec supporting applications. See the Photoshop filter test results for examples of the boost that Altivec can provide.

Since the iMAXpowr G4/433 runs at nearly twice the clock speed of my original iMac G3/233 (as well as having twice the backside cache), even without Altivec support performance improvements were impressive.

What Applications Benefit from Altivec?
For a complete list, see the Apple G4 section of the FAQ.

About OS 9 and G4 Upgrades: [NOTE: This review was written long before OS 9.1 was released - OS 9.1 does not have the extensions below (doesn't need them) and will remove them if they exist during an OS 9.1 update. For see this related article on OS 9.1.] As noted on my Nov 13th 1999 weekend news page and in the previous XLR8 G4/400 ZIF review, if you install OS 9 on a G4 CPU upgraded Mac, the 4 OS 9 Altivec extensions are not normally installed. (Note: These 4 extensions are only a part of OS 9.0 and OS 9.04 - not OS 9.1) These 4 used by OS 9.0 and OS 9.04 extensions are:

  • vBasicOps
  • vBigNum
  • vectorOps
  • vMathLib (updated again in OS 9.04)

Although I'm told that selecting a customized OS 9 install and choosing a "Universal" OS 9 installation will install them, a simpler way is to use Tome Viewer ( to extract the specific files from the installer. Point Tome Viewer at Mac OS 9:Software Installers:System Software:Mac OS 9 Additions:Tome.

Review Tests/Ratings:

  1. BenchMark Performance: Includes MacBench 5.0 CPU, FPU, Disk and Graphics tests. GaugePro memory bandwidth tests are also listed.
  2. Applications/Game Performance: How the upgrade performed in real world CPU intensive tests like Photoshop 5.5, SoundJam MP, Infini-D, After Effects, Bryce and demanding 3D games.
  3. Software Controls: Ease of use and features of the supplied control software.
  4. Installation: Comments on the installation procedure and notes on documentation.
  5. Specs/Design: Features and details on the hardware design.
  6. Summary: Final comments, summary and pricing/availability.


The iMAXpowr G4 is compatible with the following iMac versions:

  • Apple iMac rev A through D (233Mhz, 266MHz and 333MHz models)

OS Version Compatibility:

Altivec support requires Mac OS 8.6 or later (OS 9.04 preferred). Newer Tech also notes the iMAXpowr is OS X compatible (they have beta tested it under OS X).

Test System Hardware Summary

  • Apple iMac rev A (G3/233)
  • 192MB RAM
  • Stock 4GB IDE hard drive (95% full)
  • Original CDROM drive
  • ATI RageII onboard video (6MB SDRAM)
  • iMac Game Wizard Voodoo2 card (using 3dfx B5 drivers)
  • All OS 9 Altivec extensions were enabled for G4 CPU tests
  • OS 9.04, VM off, QT 4.1,OpenGL 1.1.3, [No Libmoto]

Comparison System: I used an Apple iMac DV SE (reviewed previously) for performance comparisons. The DV SE iMac has a faster system bus (100MHz vs 66MHz), much larger hard drive and faster onboard controller as well as other features like firewire. See the previous review of that system for more details.

You can follow my preferred path through the review by continuing to the next page, or use the links below to jump to a specific page.

Index of Newer Tech iMAXpowr G4 433MHz Review

Intro | Benchmarks | Appl/Game Tests | Software Controls | Installation | Specs/Design | Summary

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