Yeah, "Hexium" didn't quite work, and they thought they'd already gotten
a working brand with "Pentium". That it clashed with their previous
public prerelease naming scheme of P+number ("P", I believe, for
"project" or "processor") didn't matter.
The Pentium 4 is properly called the P7, but almost noone calls it that.
"Pentium" is also a highly unstable isotope of hydrogen (Hydrogen-5),
with a half-life under a zeptosecond.
-hpa
--