The microprocessor that was Intel Corporation's successor to the Pentium II, introduced in 1999 with a 500 MHz clock rate. The Pentim III is very similar to the Pentium II in architecture. Its external bus can be clocked at 100 or 133 MHz, it can have up to 512 KB of secondary cache, and it comes in various packages including SECC2 and FC-PGA.
The Pentium III has a P6 Dynamic Execution microarchitecture, a multi-transaction system bus, and MMX, like the Pentium II. It adds Dual Independent Bus (DIB) Architecture, the Intel Processor Serial Number, Internet Streaming SIMD Extensions and 70 new instructions. Some versions also include an Advanced Transfer Cache and Advanced System Buffering.