Third party guides and "how to" documents of all kinds are frowned upon by the OpenBSD Project. They are frequently out-of-date, often incorrect, if correct only applicable to a subset of user environments, and often written by justifiably proud newbies who may not understand the implications or limitations of what they have written.
In this case, you are referencing a guide that is more than 11 years old.
Here is a recent misc@ thread about another third party site which is very popular among newbies for OpenBSD "optimization" guidance. The thread begins here, and goes a very long way:
http://marc.info/?l=openbsd-misc&m=134327905918091&w=2