Code-named P5, the Intel Pentium was released by Intel on March 22, 1993, as a replacement to the 80486 processor and originally sold for $878.00. The name comes from the Greek word for "five" and is used because it's the fifth processor in the 80x86 line. It would have been called the 80586 had a US court not ruled that you cannot trademark a number. The Intel processors were available between speeds of 60 MHz and 300 MHz, had a 64-bit data bus, and had 1.9 million more transistors when compared to the 80486DX (3.1 million). Below is a graphic illustration of the Pentium processor.
The original Intel Pentium was released using a 273-pin PGA form factor and ran on 5v power. Intel later announced the release of a second-generation introduced on March 7, 1994, included new processors from 75, 90, 100, 120, 133, 150, 166, and 200 MHz. The processors used 296-pin SPGA form factor that is physically incompatible with the first generation versions. The third generation of Pentium processors, code-named P55C, was introduced in January 1997, which incorporated the new technology MMX. The Pentium MMX processors were available 166, 200, 233 MHz, and 266 MHz mobile version.