Simplify the following text for a Grade 10 native English-speaking person.
Original: It was popularized by Intel who developed the Pentium 1 , Pentium 2 , Pentium 3 , Pentium 4 and Pentium D processors .
Simplified: In 2003 , Intel introduced a new processor based on the P6 microarchitecture called Pentium M , which was much more power efficient than the Mobile Pentium 4 , Pentium 4 M and Pentium III M. Dual-core version of the Pentium M was developed under the code name Yonah and sold under the marketing names Core Duo and Pentium Dual-Core . Unlike Pentium D , it integrated both cores on a single chip .