- Apple's Performance Developer Portal - HTML - There are links to lots of good stuff, that I won't duplicate here. Except two technotes, which are not quite as easily accessible.
- TN2086: Tuning for the G5: A Practical Guide - HTML - Contains lots of good tips.
- TN2087: PowerPC G5 Performance Primer. - HTML - Even more good tips.
- PowerPC Compiler Writer's Guide - PDF - This is a very good book for writing good power pc assembler code.
- Writing Optimized C and C++ for a Register-based Machine - PDF - Some of the advice is good (external variables), and some is a little suspect (placement of local variable declarations), but a quick read.
- Optimizing C+ - HTML - The book is actually misnamed as it deals more with specific algorithms. Worth a look if you are dealing with large files for example.