- command line utility to test 'most' of the available memory (but not all). Can be run in Single User Mode and test all but about 60MB RAM.

- GUI version of memtest (4.05 currently) Download
Disk Test (Hard-Diskcorruption_test Folder.sit).

MacIntouch BAD RAM Report
More about reseat RAM, using a pencil eraser to clean contacts, and to be careful when installing RAM in G5s.

DIMM First Aid
DIMM First Aid 1.2 on Version Tracker

- A great explanation of why and what SDRAM specs and Apple's G4 firmware are all about, with note about chips per bank, and compatible systems (only for PC100/133, not compatible with DDR or PC2100 or later).

DFA was developed after Apple G4 firmware update started requiring the SPD code be present in order to be used. If SPD is present, DFA returns "OKAY" otherwise it will try to "repair" or not present, as well as tell you what is found.
Don't take "OKAY" as meaning it passed any other testing.

MacInTouch "Bad RAM?"
Crucial Library
Crucial Memory Glossary
Crucial FAQ
Crucial: Apple Selection Guide

Ars: Understanding Latency and bandwidth

<LI> Understanding DDR Serial Presence Detect (SPD) Table
<LI>Crucial Technologies Support page
<LI> Crucial KB
<LI>Kingston Technology's Ultimate Memory Guide
<LI>Micron Technology DRAM Product Guide
<LI>Samsung Semiconductor's Support web page
<LI>How Stuff Works: DDR RAM
<LI>Tom's Hardware Guide: DDR SDRAM
iBook Upgrades
PDF Manual: Adding RAM Customer Installable Parts
iBook Specification
iBook Discussions
SO-DIMM specifications

G5 Memory Specs Apple KB #86414
Apple's PDF on G5 Memory
Apple Discussions: biggest thread on G5 memory

PPCNUX - Memory Performance Benchmark
System Profile should show if they are working as one.
I assume it enables DDR or 128-bit vs 64-bit.
G5 test bus utility download
iMac G5 RAM Upgrade
MacMini RAM Expansion

Apple Tech Note QA1191 PC2700 in MDD
PowerMac G4 Dev Note