The Big Processor Guide - Cancelled Cores
This page is a rough guide to some of the more significant cores that have been cancelled over the years. It is not comprehensive, and is really more a compilation of some trivia on the cores that almost were.
Athlon XP Thunderbird-S: An aborted attempt to move to a 90 nm process. As it turns out, it would take a good while for AMD to make the jump.
Athlon Ultra Mustang: This would have been a follow-up to the Athlon, on Slot A. The Socket A Athlon XP won out.
Duron Appaloosa: Replaced by Applebred.
Pentium 4 Tejas: Was to be the last Pentium 4 or the first Pentium 5 (depending on who you ask), but it was cancelled to make room for the Pentium D.
Xeon Jayhawk: Would have been the Xeon counterpart to Tejas.
Pentium III Coppermine-T: Originally slated to be a bridge between the Coppermine and Tualatin, this chip was cancelled on its way to production because chipset changes rendered it unnecessary.