IBM’s developerWorks has published the fifth and last part of the series “Cook up websites fast with CakePHP”. This part deals with caching to improve the performance of an application.
Read the article (no registration needed), or have a look at the other parts of this series.

Odd, can’t find the pdf
(even more odd that you don’t have to be registered anymore)
Well, IBM uses a bit a strange system: they distinguish between article and tutorial. For tutorials there are PDFs available, but you have to be registered to read the tutorials online, and articles can be read online without registration, but they are not available as PDFs.