For the most part, however, a Celeron CPU and a Pentium III CPU running at the same clock speed deliver about the same performance, even though a Celeron-powered system costs hundreds of dollars less. Back then, a Pentium chip included 3.1 million transistors. Two years later, Intel released the Pentium Pro, which had 5.5 million transistors, and added 16 KB of cache memory, speeding up the computer by putting commonly used instructions closer to the CPU itself. The Pentium II also added something called a level-two memory cache, a separate chip with 512 KB of memory for storing previously accessed data. The Pentium II uses what is called a 0.25-micron manufacturing process.
Smaller lines allow a chip to achieve faster speeds while using less power.
Today, the Pentium II is available in clock speeds that range from 233 MHz to 450 MHz. Depending on the clock speed, a Pentium II comes with a system bus speed of either 66 MHz or 100 MHz. The system bus is the pathway along which data flows between computer components. Faster, of course, is better. In 1998, Intel added the Celeron to its line of CPUs.