Review of Powerlogix's G3 800MHz ZIF CPU Upgrade

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Review: Powerlogix's G3/800MHz ZIF CPU Upgrade
Tests in B&W G3 vs. various G3 and G4 CPU Upgrades
By Mike B.
Published: 3/25/2003

Software Controls for Powerlogix G3/800 ZIF Module

Intro | Benchmarks | Apps/Game Tests | Software Controls | Installation | Specs/Design

Powerlogix's G3/800 ZIF doesn't require any software to enable the (on-chip) L2 cache of the CPU upgrade. However they sent a beta version of their control software that allows the user to change (on the fly) the 750FX's CPU speed (and since the L2 cache is on-chip, the cache speed also changes). The 750FX G3 is the first PowerPC CPU that has the ability to set the PLL (bus/cpu ratio) setting via software. (Previous G3 and G4s have been able to have the L2/L3 cache speed changed via software, but not the CPU speed.) Although with the stock B&W G3 heatsink 900MHz wasn't reliable after about 1/2 hour of use with this sample - your mileage may vary with another sample or a better heatsink and/or fan.
Here are screenshots of each of the pages/tabs of the Powerlogix Control Software:
(most taken in OS 9, although one was taken in OS X using Grab to capture the speed settings listing with the mouse down)
Note: Powerlogix now calls this control software "CPU Director". You can download it from the Powerlogix site CPU Director page. (Updated to 1.4f1 in April 2004. This review used the first release version from March 2003.)

PL System profile tab

PL L2 Tab

PL PLL Tab
Note: The "Set PLL on Restart" option allows making the change the default at each boot. (Otherwise you can change the setting on the fly and at the next reboot CPU speed will be back at the default switch setting.)
I didn't have a capture utility for OS 9 that allowed captures with the mouse down so I used Grab in OS X to capture the settings shown when pressing on the "new setting" button. See image below:

PL G3 800 PLL/speed Control screen
Screenshot w/Speed Settings Shown
(Selection range possible, higher speeds will not be reliable w/G3 800 chip)

PL Options Tab

PL Info Tab

Apple System Profiler Notes:
In OS 9.2, Apple System Profiler reported the G3/800 as running at 300MHz speeds (speeds were also not correctly reported in older utilities like GaugePro, although Powerlogix's utilities correctly report speeds.)
OS X's Apple System Profiler did report the G3/800 running at 800MHz, however when I changed the speed to 900MHz using PL's software control (performance tests show it was running faster), Apple System Profiler in OS X (10.1.5) still reported 800MHz. Even after a reboot with the "Set PLL on Restart" set to 900MHz, ASP still reported 800MHz. Just a FYI to readers about reported speeds with ASP. When I first saw the ASP clock speed error in OS 9 I wrote Powerlogix:

" The 750fx has a 5 bit PLL; ASP looks for only 4 of the bits hence it shows the wrong speed.
Robert Jagitsch (President, Powerlogix) "

Since OS X ASP reported the correct default speed (800MHz) I expected it to show the correct boosted speed. (OS 9 ASP was inaccurate at the default 800MHz.)

The next page covers installation of the CPU upgrade. Or you may use the links below to jump to a specific page.

Index of PL G3/800 ZIF Review Pages
Intro | Benchmarks | Apps/Game Tests | Software Controls | Installation | Specs/Design

- or -
Back to WWW.XLR8YOURMAC.COM

Copyright © 2003 All rights reserved

All brand or product names mentioned here are properties of their respective companies.

Users of the web site must read and are bound by the terms and conditions of use.

The Source for Mac Performance News and Reviews
Review: Powerlogix's G3/800MHz ZIF CPU Upgrade Tests in B&W G3 vs. various G3 and G4 CPU Upgrades By Mike B. Published: 3/25/2003
Software Controls for Powerlogix G3/800 ZIF Module
Intro \| Benchmarks \| Apps/Game Tests \| Software Controls \| Installation \| Specs/Design

Powerlogix's G3/800 ZIF doesn't require any software to enable the (on-chip) L2 cache of the CPU upgrade. However they sent a beta version of their control software that allows the user to change (on the fly) the 750FX's CPU speed (and since the L2 cache is on-chip, the cache speed also changes). The 750FX G3 is the first PowerPC CPU that has the ability to set the PLL (bus/cpu ratio) setting via software. (Previous G3 and G4s have been able to have the L2/L3 cache speed changed via software, but not the CPU speed.) Although with the stock B&W G3 heatsink 900MHz wasn't reliable after about 1/2 hour of use with this sample - your mileage may vary with another sample or a better heatsink and/or fan. Here are screenshots of each of the pages/tabs of the Powerlogix Control Software: (most taken in OS 9, although one was taken in OS X using Grab to capture the speed settings listing with the mouse down) Note: Powerlogix now calls this control software "CPU Director". You can download it from the Powerlogix site CPU Director page. (Updated to 1.4f1 in April 2004. This review used the first release version from March 2003.) Note: The "Set PLL on Restart" option allows making the change the default at each boot. (Otherwise you can change the setting on the fly and at the next reboot CPU speed will be back at the default switch setting.) I didn't have a capture utility for OS 9 that allowed captures with the mouse down so I used Grab in OS X to capture the settings shown when pressing on the "new setting" button. See image below: Screenshot w/Speed Settings Shown (Selection range possible, higher speeds will not be reliable w/G3 800 chip) Apple System Profiler Notes: In OS 9.2, Apple System Profiler reported the G3/800 as running at 300MHz speeds (speeds were also not correctly reported in older utilities like GaugePro, although Powerlogix's utilities correctly report speeds.) OS X's Apple System Profiler did report the G3/800 running at 800MHz, however when I changed the speed to 900MHz using PL's software control (performance tests show it was running faster), Apple System Profiler in OS X (10.1.5) still reported 800MHz. Even after a reboot with the "Set PLL on Restart" set to 900MHz, ASP still reported 800MHz. Just a FYI to readers about reported speeds with ASP. When I first saw the ASP clock speed error in OS 9 I wrote Powerlogix: " The 750fx has a 5 bit PLL; ASP looks for only 4 of the bits hence it shows the wrong speed. Robert Jagitsch (President, Powerlogix) " Since OS X ASP reported the correct default speed (800MHz) I expected it to show the correct boosted speed. (OS 9 ASP was inaccurate at the default 800MHz.)
The next page covers installation of the CPU upgrade. Or you may use the links below to jump to a specific page.
Index of PL G3/800 ZIF Review Pages Intro \| Benchmarks \| Apps/Game Tests \| Software Controls \| Installation \| Specs/Design - or - Back to WWW.XLR8YOURMAC.COM
Copyright © 2003 All rights reserved All brand or product names mentioned here are properties of their respective companies. Users of the web site must read and are bound by the terms and conditions of use.