With the ascent of Gentoo and other source based Linux distros the discussion of compiler optimizations is common in the Linux user population. The big problem is that GCC's documentation does not answer all questions one might have on the various flags the compiler offers, the only place where all flags are accurately described is the source of GCC itself. In addition to that, knowing the purpose of all flags does not lead to enlightenment about the best CFLAGS for all packages, therefore I felt the need for an article about GCC which actually refers to the source code itself and which gives you further reference to benchmarks and other documentation that is available on-line. This document will describe the available optimizations of GCC for x86 Linux systems.