There are a bunch of advices there, some of them are quite sound, if not new '" like use latest versions if possible, profile your code, cache whatever can be cached, etc. Some are of doubtful value '" like the output buffering one, which could be useful in some situations but do nothing or be worse in others, and if you're a beginner generally it's better for you to leave it alone until you've solved the real performance problems.
He mentions four things that need amending from what Google suggests:
- Don't copy variables for no reason
- Avoid doing SQL queries within a loop.
- Use single-quotes for long strings
- Use switch/case instead of if/else