X86

x86, also commonly referred to as IA-32, are processors that are descendants, or share the same basic instruction set with, the original 8086 processor from Intel. With regards to Linux, it relates more to 32-bit descendants of the 80386. Processors which fall into this category, and can thus run Linux, include:

Intel

 * Intel 80386 - Referred to as i386. Very few modern distros can run on these, due to changes in GCC and glibc.
 * Intel 80486 - Referred to as i486.
 * Intel Pentium - Referred to as i586
 * Intel Pentium Pro - Referred to as i686. Most modern distros fall into this category, and are optimized for this or later processors.
 * Intel Pentium II
 * Intel Pentium III
 * Intel Celeron - Note that Celerons are stripped-down versions of the Pentium II and later.
 * Intel Pentium 4
 * Intel Xeon - Xeons are high-end versions of the Pentium II and later.
 * Intel Core - Includes Solo and Duo versions.
 * Intel Core 2 - Includes Solo, Duo, and Quad versions.

AMD

 * AMD Am386
 * AMD Am486 - i486
 * AMD 5x86 - i486
 * AMD K5 - i586
 * AMD K6 - i586
 * AMD K6-2 and K6- 3 - i586
 * AMD Athlon - i686
 * AMD Duron
 * AMD Athlon XP
 * AMD Opteron
 * AMD Athlon 64 - See also AMD64
 * AMD Athlon 64 X2
 * AMD Phenom

Cyrix

 * Cyrix 5x86 - i586?
 * Cyrix 6x86 - i586
 * Cyrix MediaGX - i586
 * Cyrix 686 - i686?
 * Cyrix M3 - i686

Via / Centaur

 * VIA C3 - i686
 * VIA C7