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Accelerate Your Mac! - the source for performance news and reviews
The Source for Mac Performance News and Reviews

PowerForce G4 card
Review: PowerForce G4 350MHz
G4 CPU Upgrade for PCI Macs
By Mike
Published: 1/23/2000
Low Priced, Compact G4 Upgrade For PCI Macs
Intro | Benchmarks | Appl. Tests | Software Controls | Installation | Specs/Design | Summary
Introduction
Powerlogix's PowerForce G4 upgrade for PCI Macs allows owners of older Macs to upgrade to the same CPU as in Apple's latest systems for under $600. Since most of the current software does not take advantage of the 'Velocity Engine' (Altivec extensions) in the G4 CPU, much of the power of the G4 is untapped. However as shown on the Application Tests page (Photoshop 5.5/SoundJam MP tests) and the G4timedemo results on the Benchmarks page, a G4 CPU running software that does use Altivec can show dramatic performance increases. As more software is updated for Altivec support, owners of G4 CPUs will see immediate benefits without having to upgrade their CPUs again.

Although I normally test in more than one Mac model for many reviews of CPU card slot upgrades, due to some issues I initially had with several applications in OS 9 (SoundJam MP 1.6, OpenGL games and Virtual PC 3.0) in the 9600/350 test system (PCI SCSI card slot related), I was not able to do this for the PowerForce G4. My heavily upgraded Genesis, I suspect due to running non-Apple disk drivers, has been unable to run any brand of G4 upgrade card to date reliably. (However one of its two PCI SCSI cards is in a lower PCI slot as well, which is also likely a reason for the problems after discovering this issue in the 9600/350.)

After reinstalling applications and the OS, swapping CPU cards (from the stock 604 card to other brands of G4 upgrades), trying different bus/cpu/cache speeds, etc. I finally solved the 9600/350's G4 upgrade problems by moving my Atto Ultra2 SCSI card to one of the upper 3 PCI slots. With the PCI SCSI card in slot 4, Virtual PC 3.0, Soundjam MP 1.6 and OpenGL games would all freeze during operation. Moving the card to the upper PCI slots solved all these issues. (Note the SoundJam MP 1.6 and OpenGL game problems were seen with another brand of G4 upgrade card as well, not just the PowerForce G4.) Had I been using the stock onboard SCSI drive this would not have been an issue. OS 9 was installed on the U2 SCSI drive connected to the PCI SCSI card, which was used for all tests in this review. Complete details on the 9600/350 test system are listed below.


This page of the review describes some general things to be aware of with G4 CPU upgrades, lists system compatibility information and an overview of the other 6 pages of this review (benchmark tests, application tests, software controls, the upgrade's hardware details and a review summary). If you like, you can immediately jump to specific pages of interest with the links listed at the top and bottom of each review page.


What Applications Benefit from Altivec?
As far as mainstream commercial applications, SoundJam MP and Photoshop 5.5 (with Adobe's Altivec extensions) both show a marked advantage with the G4 CPU. In tests with the latest release of the Adobe Photoshop 5.5 Altivec extensions, I saw increases of up to 4.5x on some filter operations (Lighting Effects being the biggest gainer) over a 604 CPU of the same speed (MHz) - very impressive.

SoundJam MP showed an appx. 50% boost from the G4 over the same speed G3 CPU. Even the latest OpenGL 1.1.2 contains some Altivec optimizations and more applications should follow suit in the future. Until then, remember that most of the G4's power remains untapped with software that doesn't use Altivec extensions (currently that's about 99% of available titles). The potential for graphics applications is seen in tests like G4Timedemo that show nearly double the performance with a G4 CPU over the same speed G3 or 604. Results with all these programs and more are shown on the Applications Performance page of this review.

About OS 9 and G4 Upgrades: As noted on my Nov 13th weekend news page and in the previous XLR8 G4/400 ZIF review, if you install OS 9 on a G4 CPU upgraded Mac, the OS 9 Altivec extensions present on Apple's G4 systems are not normally installed. The 4 OS 9 Altivec extensions are:

  • vBasicOps
  • vBigNum
  • vectorOps
  • vMathLib
OS 9 Altivec extensions

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

OS Requirements for Altivec Support: Although OS 8.1 ran the G4 upgrade card fine, remember that OS 8.6 or later is required for Altivec support. (Powerlogix's Altivec Enabler with also not load under OS versions prior to 8.6.)


As with all my reviews, I include at least one other upgrade for comparison. In this review the Powerforce G4/350 is compared to the stock 9600/350 (before the upgrade) and an XLR8 G4 350 upgrade previously tested in the same 9600/350 system.

About G4 Control Software:

Be aware that the version of the G4 CPU upgrade's control software can have an effect on performance. This review includes results from other brands of G4 upgrades from previous reviews that used beta software (the latest available at the time of those reviews). Therefore current software may perform differently than the results show in this review.

The setting of G4 supervisor registers by the card's control software affects L1/L2 cache wait states, cache modes and other settings that can have a sometimes significant effect on benchmark and application's performance. Often these settings may be to address specific hardware or software compatibility issues and in some cases may be required for a specific G4 CPU stepping (revision). Errata (issues) in the G4 CPU are corrected in later revisions (steppings). Errata exists in all G4 steppings up to at least v2.7. (No G4 upgrade I've tested to date has a CPU revision later than 2.6.) However note that even the early 2.2 revision G4 CPUs perform well, often better than later revisions (again depending on the control software's register settings and selected cache control mode settings). Bottom Line is don't consider minor differences in performance with G4 cards as significant, as later software revisions or different cache mode (write-through or write-back) settings can affect results.


Review Tests/Ratings:

  1. BenchMark Performance: Includes MacBench 5.0, G4Timedemo, Memory Bench, and GaugePro.

  2. Applications Performance: How the upgrade performed in real world CPU intensive tests like Infini-D, After Effects, Virtual PC 3.0 and demanding 3D games like Quake3 Arena and Unreal. To illustrate the advantage of the G4's Altivec ('Velocity Engine'), tests were also run with Soundjam MP v1.6 and Photoshop v5.5 with the latest Altivec plug-ins.

  3. Software Controls: Ease of use and features of the supplied control software. Also includes important information on Speculative Access and Cache Control settings.

  4. Installation: This page has a overview and summary of software and hardware installation. Also included is a guide to troubleshooting should problems arise.

  5. Specs/Design: Features and details on the hardware design. Includes package contents, warranty and compatibility information.

  6. Summary: Final comments, summary and pricing/availability.


System Compatibility:

The PowerForce G4 is listed as compatible with the following Mac models:

  • Apple PowerMac 7300, 7500, 7600, 8500, 8600, 9500 & 9600
  • Umax S900 and J700
  • PowerComputing PowerBase, PowerWave, PowerTower Pro (but not the PowerTower)
  • Daystar Genesis/Millennium

Currently the PowerForce G4 is the only G4 CPU upgrade compatible with the PowerBase. Note that unlike G3 CPU upgrades, no current G4 upgrade is compatible with Catalyst motherboard based Macs like the PowerCenter/PowerCenter Pro and PowerTower models. (PowerTower Pro models are based on a different motherboard and are listed as compatible.)

.



Test System Hardware Summary

  • Apple PowerMac 9600/350
  • 320MB Interleaved RAM
  • ATTO ExpressPCI Ultra2 SCSI card
  • Seagate Cheetah 4.5GB U2 SCSI drive (used for all tests)
  • Stock 4GB SCSI hard drive (5400 rpm, 512KB cache)
    [This drive conained OS 8.1 and was not used in tests for this review]
  • Apple 24x CDROM drive (OEM)
  • OEM SCSI ZIP drive
  • ATI Rage128 OEM rev1 graphics card (from B&W G3 rev 1)
    (this card has a slower clock speed than rev 2 or retail Rage128 versions)
  • All OS 9 Altivec extensions were enabled for G4 CPU tests
  • OS 9.0, VM off, QT 4.0.3, QD3D 1.6., OpenGL 1.1.2, [No Libmoto]
  • Dual 3Dfx Voodoo2 PCI cards (used for Unreal game tests in SLI mode)

For tests in Quake3 Arena (retail), a PCI 3dfx Voodoo3 2000 card using the current Beta10 drivers was used.


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 PowerForce G4 350MHz Review Pages

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

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